Spring materials

Carbon steels

  • Hard-drawn spring steel
    Low cost; general purpose; low stress; low fatigue life. Temperatures below 120°C. Tensile strength up to 1600 N mm -2.
  • Piano (music) wire
    Tougher than harddrawn spring steel; high stress (tensile strength up to 2300 N inm- *); long fatigue life; used for 'small springs'. Temperatures below 120°C.
  • Oil-tempered spring steel
    General purpose springs; stress not too high; unsuitable for shock or impact loads. Popular diameter range 3-15 mm.

Alloy steels

  • Chrome-vanadium steel
    Best for shock and impact loaL,. Available in oiltempered and annealed condition. Used for internal combustion engine valve spriags. Temperatures up to 220 "C.
  • Silicon-manganese steel
    High working stress; used for leaf springs; temperatures up to 220°C. Si1 icon-chromium steel Better than silicon-manganese; temperatures up to 220 "C.
  • Stainless steels
    Cold drawn; tensile strength up to 1200Nmm-2. Temperatures from sub-zero to 290 "C, depending on type. Diameters up to 5mm.

Non-ferrous alloys

  • Spring brass (70/30)
    Low strength, but cheap and easily formed. Good electrical conductivity.
  • Phosphor bronze (5%Sn)
    High strength, resilience, corrosion resistance and fatigue strength. Good electrical conductivity. Tensile strength 770N mm-2. Wire diameters 0.15-7mm. Used for leaf and coil switch springs.
  • Beryllium-copper (2 1/4%)
    Formed in soft condition and hardened. High tensile strength. Used for current-carrying brush springs and contacts. Tensile strength 1300Nmm-2.
  • Inconel
    Nickel based alloy useful up to 370°C. Exceedingly good corrosion resistance. Diameters up to 7mm. Tensile strength up to 1300Nmm-2.

Moduli of spring materials

Material

Modulus of rigidity, G, GNm-2

Modulus of elasticity, E,GNm-2

Carbon steel

80

207

Chromevanadium
steel

80

207

1818 Stainless steel

63

193

70130 Brass

38

103

Phosphor bronze

36

97

Beryllium copper

40-48

110-128

Inconel

76

214

Monel

66

179

Nickel-silver38

38

110

Cast irons

Grey iron
Grey iron is so called because of the colour of the fracture face. It contains 1.543% carbon and 0.3-5% silicon plus manganese, sulphur and phosphorus. It is brittle with low tensile strength, but is easy to cast.

Properties of some grey irons (BS 1452)

Grade

Tensile strength (Nmm-2)

Compressive strength (Nmm-2)

Transverse strength (Nmm-2)

Hardness, BHN*

Modulus of elasticity (GN m-2)

10

160

620

290-370

160-180

76-104

17

260

770

450-490

190-250

110-130

24

370

1240

620-700

240-300

124-145

Spheroidal graphite (SG) iron

This is also called nodular iron because the graphite is in the form of small spheres or nodules. These result in higher ductility which can be improved further by heat treatment. Mechanical properties approach those of steel combined with good castability.

Properties of some SG irons (BS 2789)

Grade

Tensile strength (Nmm-2)

0.5% permanent set stress (Nmm-2)

Hardness, BHN*

Minimum elongation (%)

SNG24/17 370 230 140-170 17
SNG37/2 570 390 210-310 2
SNG47/2 730 460 280-450 2

Malleable irons

These have excellent machining qualities with strength similar to grey irons but better ductility as a result of closely controlled heat treatment. There are three types: white heart with superior casting properties; black heart with superior machining properties; and pearlitic which is superior to the other two but difficult to produce.

Properties of some maUeabie irons

Type

Grade

Minimum Tensile strength (Nmm-2)

Yield Point strength (Nmm-2)

Hardness, BHN*

elongation (%)

White heart, BS 309

W22/24

310-340

180-200

248(max.)

4

White heart, BS 309

W24/8

340-370

200-220

248(max)

6

Black heart, BS 310

B18/6

280

170

150(max)

6

Black heart, BS 310

B20/10

310

190

150(max)

10

Black heart, BS 310

B22/14

340

200

150(max)

14

Pearlitic, BS 3333

P28/6

430

-

143-187

6

Pearlitic, BS 3333

P33/4

460

-

170-229

4

* BHN : Brinell Hardness Number

Metal processes

Metals can be processed in a variety of ways. These can be classified roughly into casting, forming and machining. The following table gives characteristics of different processes for metals, although some may also apply to non-metallic materials such as plastics and composites.

General characteristics of metal processes :

Process

Economic quantity

Materials (typical)

Optimum Size

Minimum section (mm)

Holes Possible

Inserts possible

Sand casting

Small/barge

No limit

1-100 kg

3

yes

yes

Die casting, gravity

large

AI, Cu, Mg,Zn alloys

1- 50 kg

3

yes

yes

Die casting, pressure

large

AI, Cu, Mg,Zn alloys

50g-50kg

1

yes

yes

Centrifugal casting

large

No limit

30mm-1m diameter

3

yes

yes

Investment casting

small/large

No limit

50g-50kg

1

yes

yes

Closed die forging

large

No limit

3000cm3

3

yws

yes

Hot extrusion

large

No limit

500mm diameter

1

-

yes

Hot rolling

large

No limit

-

-

no

no

Cold rolling

large

No limit

-

-

no

no

Drawing

small/large

AI,Cu,Zn,mild steel

3mm/6m diameter

0.1

no

yes

Spinning

one-off, large

AI,Cu,Zn,mild steel

6m/4.5m diameter

0.1

no

yes

Impact extrusion

large

AI, Pb, Zn,Mg, Sn

6-100mm diameter

0.1

-

no

Sintering

large

Fe, W, bronze

80g-4kg

0.5

yes

yes

Machining

one-off, large

No limit

-

-

yes

yes

Non-ferrous metals

Electrolytically refined copper (99.95% Pure) is used for components requiring high conductivity. Less Pure copper is used for chemical plant, domestic plumbing, etc. Copper is available in the form ofwire, sheet, strip, plate, round bar and tube. Copper is used in many alloys, including brasses, bronzes, aluminium bronze, cupronickel, nickel-silver and bryllium-copper.

Composition and mechanical properties of some copper alloys

Type and uses

Cu (%)

Zn (%)

Other

Condition

0.1 proof stress (N mm-2)

Tensile strength (N mm-2)

Elongation (%)

Vickers hardness

Muntz metal: die tampings, and extrusions

60

40

-

Extruded

110

350

40

75

Free-cutting brass: high-peed machining

58

39

3 Pb

Extruded

140

440

30

100

Cartridge brass: severe cold working

70

30

-

Annealed

75

270

70

65





Work hardened

500

600

5

180

Standard brass: presswork

65

35

-

Annealed

90

320

65

65





Work hardened

500

690

4

185

Admiralty gunmetal: general-purpose castings

88

2

10 Sn

Sand casting

120

290

16

85

Phosphor bronze: castings and bushes for bearings

remainder

remainder

10 Sn 0.03-0.25 P

Sand casting

120

280

15

90

Alloy steels

Classification
Alloy steels differ from carbon steels in that they contain a high proportion of other alloying elements. The following are regarded as the minimum levels:

Element

%

Element

%

Element

%

Aluminium

0.3

Lead

0.1

Silicon

2.0

Chromium

0.5

Manganese and silica

2.0

Sulphur and phosphorus

0.2

Cobalt

0.3

Molybdenum

0.1

Tungsten

0.3

Copper

0.4

Nickel

0.5

Vanadium

0.1

Alloy steels are classified according to increasing proportion of alloying elements and also phase change during heating and cooling as follows:
low alloy steels
medium alloy steels
high alloy steels
and according to the number of alloying elements as follows:
ternary - one element
quarternary - two elements
complex - more than two elements

General description

Low alloy steels

These generally have less than 1.8% nickel, less than 6% chromium, and less than 0.65% molybdenum. The tensile strength range is from 450-620 N mm-’ up to 85O-1000 N mm-2

Medium alloy steels

These have alloying elements ranging from 5-12%. They do not lend themselves to classification. They include: nickel steels used for structural work, axles, shafts, etc.; nickel-molybdenum steels capable of being case-hardened, which are used for cams, camshafts, rolling bearing races, etc.; and nickelchromemolybdenum steels of high strength which have good fatigue resistance.

High alloy steels

These have more than 12% alloying elements. A chromium content of 13-18% (stainless steel) gives good corrosion resistance; high wear resistance is obtained with austenitic steel containing over 11%  manganese. Some types have good heat resistance and high strength.

Gas Turbine Cycle

The gas turbine is used in a wide range of applications. Common uses include power generation plants and military and commercial aircraft. In Jet Engine applications, the power output of the turbine is used to provide thrust for the aircraft.


In a simple gas turbine cycle, low pressure air is drawn into a compressor (state 1) where it is compressed to a higher pressure (state 2). Fuel is added to the compressed air and the mixture is burnt in a combustion chamber. The resulting hot products enter the turbine (state 3) and expand to state 4. Most of the work produced in the turbine is used to run the compressor and the rest is used to run auxiliary equipment and produce power.

Air standard models provide useful quantitative results for gas turbine cycles. In these models the following assumptions hold true.
  • The working substance is air and treated as an ideal gas throughout the cycle
  • The combustion process is modeled as a constant pressure heat addition
  • The exhaust is modeled as a constant pressure heat rejection process
In cold air standard (CAS) models, the specific heat of air is assumed constant at the lowest temperature in the cycle.

Brayton Cycle
The Brayton cycle depicts the air-standard model of a gas turbine power cycle.

The four steps of the cycle are:
  • (1-2) Isentropic Compression
  • (2-3) Reversible Constant Pressure Heat Addition
  • (3-4) Isentropic Expansion
  • (4-1) Reversible Constant Pressure Heat Rejection
The pv and Ts diagrams are shown below.

Carbon steels

Their use is restricted to the cutting of soft metals and wood. Performance is poor above 250°C.

High-speed Steels

These are used extensively, particularly for multi-point tools. They have been replaced to a large extent by carbides for single-point tools. Their main application
is for form tools and complex shapes, e.g. for gearcutting and broaching. They are also used for twist drills, reamers, etc.

Carbides

These consist of powdered carbides of tungsten, titanium, tantalum, niobium, etc., with powdered cobalt as binder. They are produced by pressing the powder
in dies and sintering at high temperature. They are then ground to the final shape. They are generally used as tips and can operate up to 1oo0"C.

Laminated carbide

These consist of a hard thin layer of titanium carbide bonded to a tungsten carbide body. The surface has very high strength at high temperature, whilst the body has high thermal conductivity and thus efficient removal of heat.

Diamonds

These are the hardest of all cutting materials with low thermal expansion and good conductivity. They are twice as good as carbides under compression. A good finish can be obtained with non-ferrous metals and final polishing can be eliminated. Diamonds are particularly good for cutting aluminium and magnesium alloys, copper, brass and zinc. They have a long life.

Pipe Equations

Pipe cross-sectional area, empty pipe weight, pipe filled with water weight, inside and outside pipe surface area for a unit length pipe can be calculated with the equations below.
pipe diameter cross sectional area
Cross Sectional Area
Cross-sectional Area of a Steel Pipe can be calculated as
A = 0.785 di 2
where
A = cross-sectional area of pipe (Square Inches)
di = inside diameter (inches)

Weight of Empty Steel Pipes
Weight of empty steel pipes can be calculated as
wp = 10.6802 t (do - t)
where
wp =weight of steel pipe (Pounds per Foot Pipe)
t = pipe wall thickness (Inches)
do = outside diameter (inches)

Weight of Water in Pipes filled with Water
Weight of water in pipes filled with water can be calculated as
ww = 0.3405 di 2
where
ww = weight of steel pipe filled with water (Pounds per Foot Pipe)
di = inside diameter (inches)

Outside Surface Area of Pipes
Outside surface area of steel pipes can be calculated as
Ao = 0.2618 do
where
Ao = outside area of pipe - per foot (Square Feet)
do = outside diameter (inches)

Inside Surface Area of Pipes
Inside surface area of steel pipes can be calculated as
Ai = 0.2618 di
where
Ai = inside area of pipe - per foot (Square Feet)
di = inside diameter (inches)

Area of the Metal
Area of the metal can be calculated as
Am = 0.785 (do 2 - di 2)
where
Am = area of the metal (Square inches)
di = inside diameter (inches)
do = outside diameter (inches)

The American National Standards Institute - ANSI - is a private, non-profit organization that administers and coordinates the U.S. voluntary standardization and conformity assessment system.

ANSI provides a forum for development of American national standards from organizations as

and serves as a coordination point for national distribution of international standards issued from organizations as
Many of committees are chaired and sponsored by engineering societies such as
Safety is the basic objective in the standards developed by ANSI. The ANSI standards include prohibition for practices considered unsafe.

Some of the ANSI codes may eventually become known as ASME standards - as the ANSI B31 Pressure Piping Code is changed to ASME B31.

Gas Welding

In gas welding the heat to melt the metal parts being welded is produced by the combination of oxygen and an inflammable gas such as acetylene, propane, butane, etc. Acetylene is the most commonly used gas; propane and butane are cheaper but less efficient.

Oxyacetylene welding
A flame temperature of about 3250 "C melts the metals which fuse together to form a strong joint. Extra metal may be supplied from a filler rod and a flux may be used to prevent oxidation. The gas is supplied from high pressure bottles fitted with special regulators which reduce the pressure to 0.134.5 bar. Gauges indicate the pressures before and after the regulators. A torch mixes the gases which issue from a copper nozzle designed to suit the weld size. The process produces harmful radiation and goggles must be worn. The process is suitable for steel plate up to 25mm thick, but is mostly used for plate about 2 mm thick.

Pipe Formulas

The calculator is based on the piping formulas and equations below:

Moment of Inertia
Moment of inertia can be expressed as
I = 0.0491 (do4 - di4)
where
I = moment of inertia (in4)
do = outside diameter (in)
di = inside diameter (in)

Section Modulus
Section modulus can be expressed as
Z = 0.0982 (do4 - di4) / do
where
Z = section modulus (in3)

Transverse Metal Area
Transverse metal area can be expressed as
Am = π (do2 - di2) / 4
where
Am = transverse metal area (in2)

External Pipe Surface
External pipe or tube surface per ft of length can be expressed as
Ao = π do / 12
where
Ao = external pipe surface area (ft2 per ft pipe)

Internal Pipe Surface
Internal pipe or tube surface per ft of length can be expressed as
Ai = π di / 12
where
Ai = internal pipe surface area (ft2 per ft pipe)

Transverse Internal Area
Transverse internal area can be expressed as
Aa = 0.7854 di2
where
Aa = transverse internal area (in2)

Circumference External
External circumference can be expressed as
Ce = π do
where
Ce = external circumference (in)

Circumference Internal
Internal circumference can be expressed as
Ci = π di
where
Ci = internal circumference (in)

Arc welding


The heat of fusion is generated by an electric arc struck between two electrodes, one of which is the workpiece and the other a ‘welding rod’. The welding rod is made of a metal similar to the workpiece and is coated with a solid flux which melts and prevents oxidation of the weld. The rod is used to fill the welded joint. Power is obtained from an a.c. or d.c. ‘welding set’ providing a regulated low-voltage high-current supply to an ‘electrode holder’ and ‘earthing clamp’. The work is done on a steel ‘welding table’ to which the work is clamped and to which the earthing clamp is attached to complete the circuit.


Antimony
A brittle lustrous white metal used mainly as an alloying element for casting and bearing alloys and in solders.

Beryllium
A white metal similar in appearance to aluminium. Brittle at room temperature. Has many applications in the nuclear field and for electronic tubes. With copper and nickel it produces alloys with high strength and electrical conductivity. Beryllium iron has good corrosion and heat resistance.

Cadmium
A fairly expensive soft white metal like tin. Used for plating and electrical storage batteries. It has good resistance to water and saline atmospheres and is useful as plating for electrical parts since it takes solder readily.

Chromium
A steel-grey soft but brittle metal. Small traces of carbide give it extreme hardness. It is used extensively in alloys and for electroplating and is also used for electrical resistance wire and in magnet alloys.

Lead
A heavy, soft, ductile metal of low strength but with good corrosion resistance. It is used for chemical equipment, roofing, cable sheathing and radiation shielding. It is also used in alloys for solder and bearings.

Lead-tin alloys
These are used as ‘soft solders’, often with a little antimony for strength. Tinman’s solder Approximately 2 parts of tin to 1 part of lead. Used for electrical jointing and tinplate can sealing. Plumber’s solder Approximately 2 parts of lead to 1 part of tin. Used for wiping lead pipe joints. Type metal Contains about 25% tin, with lead and some antimony. Has negligible shrinkage. Bearing metal Lead based ‘white metal’ contains lead, tin, antimony and copper, etc.

Magnesium
A very light metal, only one-quarter the weight of steel and two-thirds that of aluminium, but not easily cold worked. Usually alloyed with up to 10% aluminium and often small amounts of manganese, zinc and zirconium. Used for aircraft and internal combustion engine parts, nuclear fuel cans and sand and die castings. Magnesium and its alloys corrode less in normal temperatures than does steel.

Manganese
A silvery white hard brittle metal present in most steels. It is used in manganese bronze and high nickel alloys and to improve corrosion resistance in magnesium alloys.

Nickel
Nickel has high corrosion resistance. It is used for chemical plant, coating steel plate and electroplating as a base for chromium. Nickel is used for many steel, iron and non-ferrous alloys. Nickel-base alloys Monel Used for steam turbine blades and chemical plant. Composition: 68%Ni, 3o%cu, 2%0Fe. Inconel Good at elevated temperatures, e.g. for cooker heater sheaths. Composition:  8O%Ni, 14%Cr, 6%Fe.
Nimonic A series of alloys based on 70-80%Ni, with small amounts of Ti, Co, Fe, A1 and C. Has high resistance to creep and is used for gas turbine discs and blades, and combustion chambers. Strong up to 900 “C.

Platinum
A soft ductile white metal with exceptional resistance to corrosion and chemical attack. Platinum and its alloys are widely used for electrical contacts, electrodes and resistance wire.

Silver
A ductile malleable metal with exceptional thermal and electrical conductivity. It resists most chemicals but tarnishes in a sulphurous atmosphere. It is used for electrical contacts, plating, bearing linings and as an alloying element.

Tin
A low-melting-point metal with silvery appearance and high corrosion resistance. It is used for tinplate, bearing alloys and solder.

Titanium
An expensive metal with low density, high strength and excellent corrosion resistance. It is used in the aircraft industry, generally alloyed with up to 10% aluminium with some manganese, vanadium and tin. Titanium is very heat resistant.

Tungsten
A heavy refractory steel-grey metal which can only be produced in shapes by powder metallurgy (m.p.3410 “C). It is used as an alloying element in tool and die steels and in tungsten carbide tool tips. It is also used in permanent magnets.

Zinc
Pure zinc has a melting point of only 400 “C so is good for die casting, usually with 1-2%0Cu and 4%A1 to increase strength. Used for carburettors, fuel pumps, door handles, toys, etc., and also for galvanizing sheet steel, nails and wire, and in bronze.

Aluminium

This acts as a deoxidizer to increase resistance to oxidation and scaling. It aids nitriding, restricts grain growth, and may reduce strength unless in small quantities. The range used is 0-2%.

Chromium

A range of O M % , improves wear, oxidation, scaling resistance, strength and hardenability. It also increases high-temperature strength, but with some loss of ductility. Chromium combines with carbon to form a wear-resistant microstructure. Above 12% the steel is stainless, up to 30% it is used in martensitic and ferritic stainless steel with nickel.

Cobalt

Cobalt provides air hardening and resistance to scaling. It improves the cutting properties of tool steel with 8-10%. With chromium, cobalt gives certain high alloy steels high-temperature scaling resistance.

Copper

The typical range is 0.24.5%. It has limited application for improving corrosion resistance and yield strength of low alloy steels and promotes a tenacious oxide film.

Lead

Up to 0.25% is used. It increases machineability in plain carbon steels rather than in alloy steels.

Manganese

The range used is 0.3-2%. It reduces sulphur brittleness, is pearlitic up to 2%, and a hardening agent up to 1 Yo. From 1-2% it improves strength and toughness and is non-magnetic above 5%.

Molybdenum

The range used is 0.3-5%. It is a carbide forming element which promotes grain refinement and increases high-temperature strength, creep resistance, and hardenability. Molybdenum reduces temper brittleness in nickel-chromium steels.

Nickel

The range used is 0.3-5%. It improves strength, toughness and hardenability, without affecting ductility. A high proportion of it improves corrosion resistance. For parts subject to fatigue 5% is used, and above 27% the steel is non-magnetic. Nickel romotes an austenitic structure.

Silicon

The usual range is 0.2-3%. It has little effect below 3%. At 3% it improves strength and hardenability but reduces ductility. Silicon acts as a deoxidizer.

Sulphur

Up to 0.5% sulphur forms sulphides which improve machineability but reduces ductility and weldability.

Titanium

This is a strong carbide forming element. In proportions of O.2-O.75% it is used in maraging steels to make them age-hardening and to give high strength. It stabilizes austenitic stainless steel.

Tungsten

This forms hard stable carbides and promotes grain refining with great hardness and toughness at high temperatures. It is a main alloying element in high speed tool steels. It is also used for permanent-magnet steels

This is a carbide forming element and deoxidizer used with nickel and/or chromium to increase strength. It improves hardenability and grain refinement and combines with carbon to form wear-resistant microconstituents. As a deoxidizer it is useful for casting
steels, improving strength and hardness and eliminating blowholes, etc. Vanadium is used in high-speed and pearlitic chromium steels.

Vanadium

This is a carbide forming element and deoxidizer used with nickel and/or chromium to increase strength. It improves hardenability and grain refinement and combines with carbon to form wear-resistant microconstituents. As a deoxidizer it is useful for casting
steels, improving strength and hardness and eliminating blowholes, etc. Vanadium is used in high-speed and pearlitic chromium steels.

 

A pump does not completely convert the kinetic to pressure energy. Some of the energy is always lost internal and external in the pump.

Internal losses

  • hydraulic losses - disk friction in the impeller, loss due to rapid change in direction an velocities through the pump
  • volumetric losses - internal recirculation at wear rings and bushes
External losses
  • mechanical losses - friction in seals and bearings
pump efficiency bep

The efficiency of the pump at the designed point is normally maximum and is called the
  • Best Efficiency Point - BEP
It is possible to operate the pump at other points than BEP, but the efficiency of the pump will always be lower than BEP.

Typical properties of alloy steels

Content

Type

Specification

Tensile strength (Nmm-2)

Fatigue limit (Nmm-2)

Weldability

Corrosion resistance

Machine ability

Formability

Low

1 %Cr, Mo

709M40

1240

540

PH/FHTR

PR

F/HTR

F

Low

1.75%Ni,Cr,Mo

817M40

1550

700

PH/FHTR

PR

P/HTR

F

Low

4.25%Ni,Cr, Mo

835M30

1550

700

PH/FHTR

PR

P/HTR

F

Low

3%Cr, Mo, V

897M39

131(1780)

620

PH/FHTR

PR

P/HTR

F

Low

5%Cr, Mo, V

AISI HI 1

2010(A2630)

850 (A1880)

PH/FHTR

PR

P/HTR

F

Medium

9%Ni, Co

HP9/4/45 Republic Steel

1390 (1850)

-

FHTR

PR

P/HTR

F

Medium

12-14%Cr

410S21

1160

340

P/FHTR

F

F/HTR

F

Medium

Cr, W, Mo. V

Vascojet MA, Vanadium
alloy steel

2320 (A3090)

960

PH/FHTR

PR

P/HTR

F

High

13%Cr, Ni, Mo

316S12

620

260

G

G

F

G

High

19%Cr,Ni, Mo

317S16

650

260

G

G

F

G

High

15%Cr, Ni, Mo, V

ESSHETE 1250 S. Fox

590

-

G/FHTR

G/HT

F

-

High

17%Cr,Ni

AISI 301

740(CR1240)

280

F

F

F

G

High

17% Cr, Ni, AI

1717 PH Armco

1480

-

F

F

F

G

High

14%Cr, Ni, Cu. Mo, Nh

REX 627 Firth Vickers

1470

540

FHTR

F

F

F

High

15%Cr, Ni, Mo, V

AM 355 Allegheny Ludlum

1480

740

FHTR

F

F

F

High

18%Ni, Co, Mo

300grade maraging INCO

1930

-

G/FHTR

PR

F

P

High

18%Ni, Co, Mo

250grade maraging

1700

660

G/FHTR

PR

F

P

A = ausformed, MA = martempered, CR =cold rolled, P = poor, F = fair, G = good, PH = preheat required, PR = protection required, HT = at high temperature, HTR = when heat treated, FHTR=final heat treatment required.

DIN - Deutsches Institut für Normung, the German Institute for Standardization, is a non-governmental organization recognized by the German government as the national standards body and represents German interests at international and European level.

DIN Standards promote rationalization, quality assurance, safety, and environmental protection as well as improving communication between industry, technology, science, government and the public domain. Standards work is carried out by 26,000 external experts serving as voluntary delegates in more than 4,000 committees. Draft standards are published for public comment, and all comments are reviewed before final publication of the standard. Published standards are reviewed for continuing relevance every five years, at least.

The over 12,000 DIN standards cover a wide range of topics including: physical quantities and units, fasteners, water analysis, building and civil engineering (including building materials, construction contract procedures (VOB), soil testing, corrosion protection of steel structures), materials testing (testing machines, plastics, rubber, petroleum products, semiconductors), steel pipes, machine tools, twist drills, roller and ball bearings, and process engineering. DIN Handbooks (covering subjects such as mechanical engineering, fasteners, steel, steel pipes, and welding), and most DIN standards are available as English versions, or as English translations.

DIN standards designation
The designation of a DIN standard shows its origin (# denotes a number):
* DIN # is used for German standards with primarily domestic significance or designed as a first step toward international status
* E DIN # is a draft standard and
* DIN V # is a preliminary standard
* DIN EN # is used for German edition of European standards
* DIN ETS # is used for standards prepared by European Telecommunications Standards Institute
* DIN ISO # is used for German edition of ISO standards
* DIN EN ISO # is used if the standard as also been adopted as a European standard

Examples - DIN Standards
* DIN 75078-1 Motor vehicle for the transport of persons with reduced mobility - Part 1: Terms and definitions, requirements, tests
* DIN V 4108-4 Thermal insulation and energy economy in buildings - Part 4: Hygrothermal design values
* DIN EN 126 Multifunctional controls for gas burning appliances
* DIN EN ISO 10042 Welding - Arc-welded joints in aluminum and its weldable alloys - Quality levels for imperfections (ISO/DIS 10042:2004)

Temperature

Temperature (sometimes called thermodynamic temperature) is a measure of the average kinetic energy of a systems particles. Temperature is the degree of "hotness" ( or "coldness"), a measure of the heat intensity.

When two objects of different temperature are in contact, the warmer object becomes colder while the colder object becomes warmer. It means that heat flows from the warmer object to the colder one.

Degree Celsius (oC) and Degree Fahrenheit (oF)
Thermometer helps us determine how cold or how hot a substance is. Temperatures in science (and in most of the world) are measured and reported in degrees Celsius (oC). In the US, it is common to report temperature in degrees Fahrenheit (oF). On both the Celsius and Fahrenheit scales the temperature at which ice melts (water freezes) and the temperature at which water boils, are used as reference points.

  • On the Celsius scale, the freezing point of water is defined as 0 oC, and the boiling point of water is defined as 100 oC.
  • On the Fahrenheit scale, the water freezes at 32 oF and the water boils at 212 oF.
On the Celsius scale there are 100 degrees between freezing point and boiling point of water, compared to 180 degrees on the Fahrenheit scale. This means that 1 oC = 1.8 oF.
Thus the following formulas can be used to convert temperature between the two scales:
tF = 1.8 tC + 32 = 9/5 tC + 32 (1)
tC = 0.56(tF -32) =5/9(tF - 32) (2)
where
tC = temperature in oC
tF = temperature in o
Example - A patient with SARS (Severe Acute Respiratory Syndrome) has a temperature of 106 oF. What does this read on a Celsius thermometer?
tC = 5/9 (106-32)= 41.1 oC

Degree Kelvin - K
Another scale (common in science) is Kelvin, or the Absolute Temperature Scale. On the Kelvin scale the coldest temperature possible, -273 oC, has a value of 0 Kelvin (0 K) and is called the absolute zero. Units on the Kelvin scale are called Kelvins (K) and no degree symbol is used.
Because there are no lower temperatures the Kelvin scale do not have negative numbers.

A Kelvin equal in size to a Celsius unit: 1 K= 1 oC.
To calculate a Kelvin temperature, add 273 to the Celsius temperature:
tK = tC + 273.16 (3)

Example - What is normal body temperature of 37 oC on the Kelvin scale?
tK = tC + 273.16 = 37 + 273.16 = 310.16 K

Degree Rankine - R
In the English system the absolute temperature is in degrees Rankine (R), not in Fahrenheit:
tR = tF + 459.69 (4)

Density
Density is defined as an objects mass per unit volume. Mass is a property.

  • Mass and Weight - the Difference! - What is weight and what is mass? An explanation of the difference between weight and mass.
The density can be expressed as
ρ = m / V = 1 / vg (1)
where
ρ = density (kg/m3)
m = mass (kg)
V = volume (m3)
vg = specific volume (m3/kg)

The SI units for density are kg/m3. The imperial (BG) units are lb/ft3 (slugs/ft3). While people often use pounds per cubic foot as a measure of density in the U.S., pounds are really a measure of force, not mass. Slugs are the correct measure of mass. You can multiply slugs by 32.2 for a rough value in pounds.
  • Unit converter for other units
The higher the density, the tighter the particles are packed inside the substance. Density is a physical
property constant at a given temperature and density can help to identify a substance.
  • Densities and material properties for common materials
Relative Density
Relative density of a substance is the ratio of the substance to the density of water, i.e.

Example - Use the Density to Identify the Material:
An unknown liquid substance has a mass of 18.5 g and occupies a volume of 23.4 ml. (milliliter).

The density can be calculated as
ρ = [18.5 (g) / 1000 (g/kg)] / [23.4 (ml) / 1000 (ml/l) 1000 (l/m3) ]
= 18.5 10-3 (kg) / 23.4 10-6 (m3)
= 790 kg/m3

If we look up densities of some common substances, we can find that ethyl alcohol, or ethanol, has a density of 790 kg/m3. Our unknown liquid may likely be ethyl alcohol!

Example - Use Density to Calculate the Mass of a Volume
The density of titanium is 4507 kg/m3 . Calculate the mass of 0.17 m3 titanium!
m = 0.17 (m3) 4507 (kg/m3)
= 766.2 kg

Specific Weight
Specific Weight is defined as weight per unit volume. Weight is a force.
* Mass and Weight - the difference! - What is weight and what is mass? An explanation of the difference between weight and mass.
Specific Weight can be expressed as

γ = ρ g (2)
where
γ = specific weight (N/m3)
ρ = density (kg/m3)
g = acceleration of gravity (m/s2)

The SI-units of specific weight are N/m3. The imperial units are lb/ft3. The local acceleration g is under normal conditions 9.807 m/s2 in SI-units and 32.174 ft/s2 in imperial units.

Example - Specific Weight Water
Specific weight for water at 39 oF (4 oC) is 62.4 lb/ft3 (9.81 kN/m3) in imperial units. Specific weight in SI units can be calculates like
γ = 1000 kg/m3 9.81 m/s2
= 9810 N/m3
= 9.81 kN/m3

Type and composition

Condition

Tensile MN/m2

Product

Use

Pure copper
99.95%Cu

O

220

Sheet, strip wire

High conductivity electrical
applications

H

350

98.85%cu

O

220

All wrought forms

Chemical plant. Deep drawn,
spun articles

H

360

99.25%cu +0.5%As

O

220

All wrought forms

Retains strength at high temperatures. Heat exchangers,
steam pipes

H

360

Brasses
9O%Cu, 10%Zn-gilding metal

O

280

Sheet, strip and wire

Imitation jewellery, decorative
work

H

510

7o%cU, 30%Zn-Cartridge brass

O

325

Sheet, strip

High ductility for deep drawing

H

700

65%Cu, 35%Zn- standard brass

O

340

Sheet, strip and extrusions

General cold working alloy

H

700

60%Cu, 40%Zn- Muntz metal

M

375

Hot rolled plate and extrusions

Condenser and heat exchanger plates

59%Cu, 35%Zn, 2%Mn,
2%A1, 2%Fe

M

600

Cast and hot worked forms

Ships screws, rudders

58%Cu, 39%Zn, 3%Pb
free cutting

M

440

Extrusions

High speed machine parts

Bronzes
95.5%Cu, 3%Sn, 1.5Zn

O

325

Strip

Coinage

H

725

5.5%Sn, O.l%Zn, Cu

O

360

Sheet, strip and wire

Springs, steam turbine blades

H

700

10%Sn, 0.03-0.25P, Cu-
phosphor bronze

M

280

Castings

Bushes, bearings and springs

10%Sn, O.S%P, Cu

M

280

Castings

General-purpose castings and bearings

10%Sn, 2%Zn, Cu-Admiralty gunmetal

M

300

Castings

Pressure-tight castings, pump,valve bodies

Aluminium bronze
95?'ocU, 5%AI

O

400

Strip and tubing

Imitation jewellery, condenser
tubes

H

770

10Y0A1, 2.5%Fe, 2-5%Ni, Cu

M

700

Hot worked and cast products

High-strength castings and
forgings

Cupronickel 75%cu, 25%Ni

O

360

Strip

British 'silver' coinage

H

600

70%Cu, 30%Ni

O

375

Sheet and tubing

Condenser tubes, good corrosion
resistance

H

650

29%cu, 68%Ni, 1.25%Fe,1.25%Mn

O

550

All forms

Chemical plant, good corrosion
resistance

H

725

Nickel-silver
55%Cu, 27%Zn, l8%Ni

O

375

Sheet and strip

Decorative use and cutlery

H

650

Ber y llium-copper
1.75-2.5%Be, 0.5% co, c u

WP

1300

Sheet, strip, wire, forgings

Non-spark tools, springs

0 =annealed, M =as manufactured, H =fully work hardened, WP=solution heat treated and precipitation hardened.

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