ME 215 – Engineering Materials I Chapter 1 Engineering Materials (Part I)

Mechanical M h i lE Engineering i i University of Gaziantep

Dr. A. D A Tolga T l Bozdana B d www.gantep.edu.tr/~bozdana

Introduction h Materials used in engineering applications cover a wide range p dailyy uses ((e.g. g p pencils,, spoons) p ) to most complex p and from simple extreme cases (e.g. space shuttles, biomedical purposes). h Properties of such materials are of joint interest to the metallurgist, the material scientist, scientist and the engineer. engineer h Compared with material scientist and metallurgist, metallurgist engineer does not require deep understanding of the subject, but needs to know which properties are important in different circumstances and what limitations he could be faced with.

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Engineering Materials Metals and Alloys Ferrous (iron based) Metals Cast Iron (%C > 2): Gray White, Gray, White Ductile, Ductile Malleable, Malleable High alloy Steel (%C < 2): Plain Carbon steels, steels Alloy steels Non-ferrous (iron free) Metals Heavy Metals: Copper, Chromium, Lead, etc. Light Metals: Titanium, Beryllium, etc.

Non-metals Naturals: Wood, Wood Granite Granite, etc. etc Artificials Polymers: Rubber, Thermoplastics, Thermosets Ceramics: Glass, Cermets Composites: Metal matrix composites, Ceramic matrix composites, composites Polymer matrix composites

Refractory (High Temp.) Metals: Tungsten, Molybdenum, etc. Precious Metals: Gold, Silver, etc. 2

Metals vs. Artificials h Metals are used to be the main engineering materials preferred y mechanical engineers g for centuries. by h The main reasons for this were their existence in nature, easy processing and also their relatively more load carrying capacity. h However, artificial materials took place in many applications due to their advantages such as better insulation, heat resistance and weight saving. h Therefore, many different materials were found or derived from other materials for certain advantages in different applications. applications

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Ferrous Metals h Ferrous metals are classified as cast irons (with > 2% C) and ) steels ((with < 2% C). h They are the most widely used materials in many engineering applications. h Steel, in particular, has many versions (alloys) with different advantages for different applications. h Steel can serve in applications varying from simple machine construction to extreme load bearing (carrying) applications and from simple springy (elastic) deflection applications to very high temperature resistant or corrosion resistant applications.

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Steel Making h Steels are made by removing excess C and other impurities of pig y “oxidation” p process followed by y “deoxidation” p process,, iron by and addition of C and other alloying elements to the required level. h Oxidation is carried out by blowing air or oxygen through molten pig iron in either of following furnaces: 1. Bessemer-Thomas Furnace 2. Siemens-Martin (Open Heart) Furnace yg Furnace 3. Basic Oxygen 4. Electric Furnace h Steels can contain up to 2% Carbon (C), 1% Manganese (Mn), 0 5% Silicon (Si), 0.5% (Si) 0.05% 0 05% Sulfur (S) and 0.05% 0 05% Phosphorus (P). (P) 5

Steel Making Flowline (AISI Flow Sheet) 5 The pig iron is either transformed into cast iron or converted into steels by a secondary process.

4 The product of blast furnace is called pig iron (i.e. impure iron) containing co ta g too much uc C, Mn,, P,, S and Si. 1 Iron is found in nature as iron ore which consist of iron oxides, carbonates and sulphides and gaunge. 2 Iron is obtained by reduction of iron oxides with carbon (i.e. coke) in the blast furnace. 3 Limestone is usually added into the blast furnace to remove gaunge (i.e. SiO2 as calcium silicate slags).

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Steel Finishing Flowline (AISI Flow Sheet)

6 The steels in the form of slabs, blooms and billets are formed into plates, coils and sheets as well as tubes, tubes bars and rods, and various structural shapes.

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Plain Carbon Steels h This is the first group of steels in which C is the significant alloying addition. They contain up to 1.5% C and also 1.65% Mn (max), 0.6% Si (max), 0.6% Cu (max). A. Low Carbon Steels 0.15% 5% C C. Very y soft,, easilyy fabricated byy cold forming g A1. Dead-soft mild steels: < 0 and welding. Used in construction where strength is not very important. A2. Mild steels: 0.15 - 0.30% C. Also known as “structural steels”. Used for structure, structure and machine applications, structural shapes like I-beams, channels, angles etc. B. Medium Carbon Steels: 0.30 - 0.60% C. Having combined properties of strength, toughness and wear resistance. Used for crankshafts, axles, railway wheels, gears. C. High Carbon Steels: 0.30 - 1.5% C. With low ductility. Used for high speed steels (HSS) wire production, (HSS), production etc. etc D. Free Machining Carbon Steels: Specially developed for fast and economic machining. Machinability of plain carbon steels is improved by addition of some elements such as Pb (lead), S, P, Te (tellurium), Se (selenium), and Bi (bismuth).

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Alloy Steels h This is the second group of steels which contain modest amount of alloying elements. They usually contain more than 1.65% Mn, 0.60% Si and 0.60% Cu. h They can be heat treated to improve some mechanical properties. They have through hardenable grades, carburizing grades, and nitriding grades. h The alloying elements to be added into alloy steels may: ƒ Form solid solution or intermetalic compounds in steel. steel ƒ Alter the temperature at which phase transformations occur. iron ƒ Alter the solubility of C in different phases of iron. ƒ Alter the rate of transformation of austenite to its decomposition products ((i.e. the solution of cementite into austenite upon p heating). g) ƒ Decrease the softening on tempering. h Nearly all alloying elements dissolve in both ferrite and austenite, and increase strength and hardenability of steels. Non-metalic inclusions (such as oxides and d sulphides) l hid ) are deoxidizers d idi and d grain i growth h controllers. ll S l hid Sulphides and d nitrides increase hardness.

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Effects of Alloying Elements h Manganese (Mn): (1.65-2.1%) increases strength, hardenability, corrosion resistance. h Titanium (Ti): increases yield point and weldability. h Wolfram or Tungsten (W): increases hardness and tensile strength. h Chromium ((Cr): ) increases hardness,, hardenability, y, wear resistance,, corrosion resistance. h Molybdenum (Mo): used with Mn & Cr to increase hardenability, tensile, creep strength. h Vanadium (V): increases hardenability. hardenability h Nickel (Ni): increases strength, shock resistance, corrosion resistance, heat resistance while lowers critical temp. temp for heat treatment. treatment h Carbon (C): increases hardness & tensile strength, decreases forging & welding properties. h Phosphorus (P): (0.03-0.05%) harmful (make steel brittle and prevent hot/cold forming). h Sulfur (S): (0.025-0.05%) harmful (make steel brittle and prevent hot/cold forming). h Aluminium (Al): promotes nitriding properties. h Silicon (Si): (0.6-2.2%) (0 6 2 2%) raises critical temp temp. for heat treatment and increases resilience. resilience h Elemental Copper (Cu) & Lead (Pb): increase machinability.

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Alaşım Elementlerinin Çeliklerin Özelliklerine Etkileri

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High Alloy Steels h They are specially produced for specific purposes by using certain alloying elements. A Tool Steels: clean (no inclusion) steels produced in electric furnaces. A. furnaces They usually contain Cr, V, W, Mo or Co besides C, Mn, Si. They have wear resistance, high g and high g hot hardness. These steels are used mainlyy in tools and dies. toughness B. Stainless Steels: contain 10.5% Cr (min). They have high strength, hardness, corrosion resistance and abrasion resistance. resistance Addition of higher amount amo nt of Cr and Ni improves corrosion resistance. C. High Strength Steels: developed for specific high strength applications and used for weight saving in constructions. D. High Strength Low Alloy (HSLA) Steels: specially developed for improving properties p and corrosion resistance while benefitting g from weight g saving. g mechanical p E. Iron Based Super Alloys: cheaper than Co and Ni based super alloys, and used for high temperature applications. applications Super alloys are usually used at temperatures from 540 to 1090 ºC. Iron based super alloys are used at lower end of this range. 12

Cast Iron h Cast iron is a “four-element alloy” containing iron, carbon (2 - 4%), g Some g grades may y contain additional silicon and manganese. alloying elements. h Cast iron contains large amount of carbon in the form of Fe3C ((cementite). ) This composition p is not stable and decomposes p under certain conditions: Fe3C → 3Fe + C h According to this breakdown of cementite, cast irons are classified: ƒ Gray CI ƒ Ductile CI ƒ White Whit CI ƒ Malleable CI ƒ High alloy CI 13

Types of Cast Iron Gray CI: h It g gives g gray y fracture surface. h Widely used in engineering applications. h In manufacture, manufacture cementite separetes into graphite and austenite or ferrite by controlling the alloy composition and cooling rates. h Most M t gray CI are “hypoeutectoid “h t t id alloys” ll ” containing t i i 2.5 2 5 - 4% C. C h Individual grades depend upon the amount of graphite distribution pattern and structure of iron around it. Ductile (Nodular) CI: h It is alloyed with magnesium which precipitates out carbon in the form of small spheres. spheres This improves some mechanical properties of gray CI. CI

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Types of Cast Iron White CI: h Produced byy “chilling” g p preventing gg graphite p carbon from p precipitating p g out. h Either gray CI or ductile CI can be chilled to produce a white surface. h Most of carbon is combined with iron as iron carbide (cementite) which is a very hard material. Grades of white CI depend on the amount of cementite in the surrounding structure. structure Malleable CI: h White CI is converted to malleable condition by two-stage heat treatment. h Malleable CI differs from others in the shape of contained graphite existing as tempered carbon nodules as compared with graphite flakes in gray CI and true carbon spheroids in ductile CI. CI h Two basic types are ferritic and pearlitic. The third type (martensitic) is pearlitic or ferritic grade that has been heat treated and transformed to martensitic structure.

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Types of Cast Iron High Alloy CI: h They y are ductile,, g gray y or white CI containing g over 3% alloyy content. h They are usually produced in specialized foundries, and their properties are significantly different from unalloyed CI. CI h Selection of the proper alloy for a casting is difficult since properties of the finished part depend strongly upon size and shape of the part. part This is very important to bear in mind when deciding on casting process.

Gray CI

Ductile CI

White CI

Malleable CI 16

Designation of Steels h There are various standardization bodies for steels: 1 American (AISI & ASTM) 1. 2. German (DIN) 3 Turkish 3. T ki h (TS & MKE) 4. British (BS) 5. Euronorm h Steels are usually designated by the criteria of: ƒ Process of manufacture ƒ Method of deoxidation ƒ Chemical composition ƒ Mechanical properties 17

Designation by Process of Manufacture h The purification of pig iron into steel is accomplished by following methods (the last two are the most widely used processes): 1. Basic Thomas or acid Bessemer converter 2. Open heart furnace 3. Electric furnace 4. Basic oxygen furnace h The prefixes are used to designate steels produced by above methods: American (AISI) standards

Turkish and DIN standards

A – Basic open hearth alloy

T – Thomas converter

B – Acid Bessemer carbon

O – Oxygen converter

C – Basic open hearth carbon

M – Open hearth furnace

D – Acid open hearth carbon

E – Electric arc furnace

E – Electric arc furnace alloy

I – Induction furnace

X – Composition varies from normal limits

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Designation by Method of Deoxidation h In steel making process, the primary reaction is the combination of carbon and oxygen to form a gas. If the oxygen is not removed prior to or during casting (by the addition of ferro-silicon or some other deoxidizer), then gaseous products continue to evolve during solidification. This will cause non-uniformity in microstructure of the steel. Proper control of the amount of gas evolved during solidification determines the type of steel. h Based on type of deoxidation, the steels are classified as below and d i designated t d by b the th letter l tt prefixes: fi Type

TS

DIN

Rimmed

K

U

Semi-killed Semi killed

Sy

H

Killed

S

R

S Specially i ll killed kill d



RR 19

Designation by Method of Deoxidation h Killed steels are completely deoxidized steels (i.e. no formation of carbon monoxide). Aluminum and silicon may be added to combine chemically with the oxygen, oxygen removing most of it from liquid steel. steel Ingots and castings of killed steels have homogeneous structure and no gas porosity (blowholes). Therefore, killed steels are recommended for hot forging, carburizing, piercing and heat-treating applications where maximum uniformity is required. hS Semi-killed (capped) ( ) steels are incompletely deoxidized steels containing some excess oxygen, which forms carbon monoxide during last stages of solidification. These steels have relatively less uniform properties and composition due to segregation (i.e. nonuniform variation in internal characteristics that results when y g elements redistribute themselves during g solidification). ) various alloying h For rimmed steels (with less than 0.25% C and 0.60% Mn), oxygen in the form of carbon monoxide mono ide evolves e ol es quickly q ickl throughout thro gho t the solidification process. process Ingots of rimmed steels are characterized by practically carbon-free surface with considerable quantity of blowholes. The outer skin of these steels is very ductile, hence they are often specified for cold-forming applications. 20

Designation by Chemical Composition h Following steel groups are designated by their chemical compositions: 1. Plain carbon steels 2. Alloy steels 3 Tool 3. T l steels t l 4. Stainless steels 5. HSLA steels 6. Super alloys

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Designation of Plain Carbon Steels h The general designation for plain carbon steels (which have only carbon as alloying element) is CiXX where “XX/100” is carbon percentage and “i” refers to grade of control of some alloying elements and some mechanical properties. properties Designation C 10 Ck 10* Cm 35 35* Cf 35* Cq 35* CC 10 S 10 C A 12 En 2C** 1225** 1010*** Ç1060*** Ç1060 St C 16.61***

C% 0 07 – 0.13 0.07 0 13 0.07 – 0.13 0 32 – 0.39 0.32 0 39 0.32 – 0.39 0.32 – 0.39 0.05 – 0.15 0.08 – 0.13 0.08 – 0.16 0.18 – 0.23 0 08 0.08 0.08 – 0.13 0 55 – 0.64 0.55 0 64 0.10 – 0.18

Designated by DIN TS DIN, DIN, TS DIN TS DIN, DIN, TS DIN, TS AFNOR (France) JIS (Japan) GOST (Russia) BS (British) SIS (Sweden) (S d ) AISI, SAE (USA) MKE (Turkey) DIN (German)

* The letters “k” and “m” designate how closely P and S content are controlled. controlled The letter “f” specifies a steel suitable for superficial hardening, and “q” specifies ifi a steel t l for f cold ld extrusion. t i ** These designations have no inference to carbon content. content “En” designation is replaced by the new “BS” designation (e.g. a steel (0.16-0.24% C) designated as “En 3” is now “BS S 070M20”).) *** “St” is the old DIN designation that is still till usedd in i Turkey T k f some steel for t l products (e.g. “16.61” is cementation steel with 0.16% C). For AISI and MKE, the numeral “1” stands for carbon steel and “10” designates plain carbon steel.

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Designation of Alloy Steels h In Turkey, mainly DIN and AISI designations are used. In DIN designation, multiplication factors are used for the content of alloying elements: Factor for Co, Cr, Mn, Ni, Si, W = x 4 Factor for Al, Cu, Mo, Ti, V

= x 10

Factor for C, N, P, S

= x 100

Steel

Average Percentage

14 NiCr 10

0.14% C, 2.5% Ni

15 CrNi 6

0 15% C 0.15% C, 1 1.5% 5% Cr

13 Cr 2

0.13% C, 0.5% Cr

16 MnCrS 5

0.16% C, 1.25% Mn

20 MoCr 4

0.20% C, 0.4% Mo

39 CrMoV 13 9 0.39% C, 3.25% Cr, 0.9% Mo 9 S 20

0.09% C, 0.2% S

X120 Mn 12

1.20% C,, 12% Mn

X12 CrNi 18 9

0.12% C, 18% Cr, 9% Ni

h If Al (0.1%), (0 1%) Cu (0.25%), (0 25%) Mn (0.8%), (0 8%) Si (0.5%) and Ti (0.1%) are not exceeded, such as steel is considered unalloyed. h Low alloy steels contain not more than 5% of alloy elements. When alloy contents exceed 5% (i.e. high alloy steels), these multiplication factors are not used (except for carbon). carbon) Instead, Instead the letter “X” is put in front of carbon content indicating that the number(s) at the end of designation specify the alloy content. 23

Designation of Alloy Steels h AISI (SAE) and MKE designations use 4-digit numbers: “XXXX” h The Th first fi t two t di it indicate digits i di t the th alloy ll classification, l ifi ti and d the th last l t two t (and in special cases, three) digits give the carbon content (x100). See next page for complete table. table h For instance, instance plain carbon steels is denoted by the basic numeral 10. 10 Thus, “Steel 1030” indicates a plain carbon steel containing 0.30% C. h In some cases, capital letter prefixes or suffixes are added to designate the type of process or hardenability. Some examples for the prefixes are: C1020 (C: for basic open heart carbon) B1112 ((B: for acid bessemer carbon)) A3140 (A: for basic open hearth alloy) E52100 (E: for electric arc furnace alloy) 24

Designation of Alloy Steels Carbon Steels

1xxx

Molybdenum Steels

4xxx

Plain Carbon

10xx

Carbon-Molybdenum

40xx

Free Cutting

11xx

Chromium-Molybdenum

41xx

Free Cutting “Leaded”

12Lxx *

Chromium-Nickel-Molybdenum

43xx

M Manganese St Steels l

13 xx

Ni k l M l bd Nickel-Molybdenum (1.75% (1 75% Ni)

46 46xx

Nickel-Molybdenum (3.50% Ni)

48xx

Nickel Steels

2xxx

3 50% Ni 3.50%

23xx

Chromium Steels

5.00% Ni

25xx

Low Chromium

51xx

Medium ed u C Chromium o u

52xx 5

Corrosion and Heat Resistant

51xx

c e C o u Steels Stee s Nickel-Chromium

3xxx 3

1.25% Ni, 0.60% Cr

31xx

1.75% Ni, 1.00% Cr

32xx

3.50% Ni, 1.50% Cr

33xx

Tungsten Steels

7xxx(x) **

Chromium-Nickel-Molybdenum

86xx, 87xx

Chromium-Vanadium Steels 1.00% Cr Silicon-Manganese Steels 2.00% Si

5xxx

6xxx 61xx 9xxx 92xx

* The letter “L” (as in 12L13 steel) signifies a free cutting steel to which lead is added to improve machinability. Likewise, the letter “B” B (e.g. 81B45) signifies a minimum of 0.0005% boron added for hardenability. The steels to meet certain hardenability requirement are designated by suffix “H” (e.g. 8637H, 94B15H, etc.) ** Used for certain tungsten alloys by SAE and MKE, such as 7245, 72100 and 71660.

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Designation of Tool Steels h These steels are divided into four broad groups as follows: Group p

German

Turkish

1

Carbon Tool Steels

Unalloyed Carbon Tool Steels

2

High-Speed High Speed Steels

Alloyed Tool Steels

3

Cold Work Tool Steels

Cold Work Tool Steels

4

Hot Work Tool Steels

Hot Work Tool Steels

Group 1: Carbon Tool Steels h Designation of carbon tool steels is the same as that of carbon steels. The only difference is that a quality symbol follows the usual designation. h The quality symbol is "W" (W1, W2, W3) denoting an increase in the quality in the order of special, p extra, best q quality. y The symbol y “WS” denotes a special p purpose tool steel (also used by Asil Çelik). h Some examples p are: C125WS ((1.25% C with special p quality), q y) C110W2, C60W3. h Designations by MKE and AISI are: Ç1090, Ç10100, Ç10115, etc. 26

Designation of Tool Steels Group 2: High Speed Steels h They are designated as: “S xx-yy-zz-uu” where “S” denotes high speed steel, “xx-yy-zz-uu” is content of W-Mo-V- Co using no multiplication factors: “S 10-4-3-10” means 10% W, 4% Mo, 3% V, 10% Co “S 18-0-1” 18 0 1” means 18% W, W 0% Mo, M 1% V, V 0% Co C Group 3 & 4: Cold & Hot Work Tool Steels h They are designated according to the designation of alloy. h DIN and ASİL Çelik uses the same designation as explained previously: “40NiMo10 8” means 0.40% C, 2.5% Ni, 0.8% Mo h MKE uses basic AISI designation for alloy steels, and tools steels are classified into groups by the AISI. All these groups of tool steels and the corresponding d i designations ti are shown h i nextt page. in

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Designation of Tool Steels (AISI designation by MKE) Cold Work Type W (water hardening)

Commercial (W1xx), Extra (W2xx), Standard (W3xx), Special (W4, W5, W6, W7)

Type O (oil hardening)

O1 O2, O1, O2 O6, O6 O7

Type A (air hardening)

A2, A3, A4, A5, A6, A7, A8, A9, A10

Type D (air hardening)

D1, D2, D3, D4, D5, D6, D7

Hot Work Type H (chromium grades) (tungsten grades)

H1 - H19 H20 - H39

(molybdenum grades) H40 - H59 High Hi h Speed S d Type T (tungsten grades)

T1, T2, T3, T4, T5, T6, T7, T8, T9, T15

Type M (molybdenum grades) M1, M2, M3-1, M3-2, M4, M6, M7, M8, M10, M15, M30, M33, M34, M35, M36, M41, M42, M43, M44, M46, M47, M50 Shock Resisting (Type S)

S1, S2, S3, S4, S5, S6, S7

Special Purpose Type P (mould steels)

P1, P2, P3, P4, P5, P6, P20, P21

T Type L (low (l alloy ll steels) t l )

L1 L2 L1, L2, L3 L3, L4 L4, L5 L5, L6 L6, L7

Type F (carbon-tungsten alloy) F1, F2, F3 28

Designation of Stainless Steels h These are widely used family of chromium alloys (min. 10.5% Cr), and they are known for their corrosion resistance. h DIN designation is the same as alloy steels: “X40 Cr 13”, “X12 CrNi 18 8”, “X20 Cr 13 13” are DIN designations of three types of stainless steel produced by MKE. MKE MKE's own designation of these steels is based on the basic SAE system: “Ç51440”, “Ç3915”, “Ç51420” in the same order. h AISI classifies wrought stainless steels into four groups based on metallurgical structure, t t and d designations d i ti are similar i il to t alloy ll steels: t l austenitic t iti (30201, (30201 30316, 30316 30347, so on); ferritic (405, 430, 442, 446, 51405 and 51430); martensitic ((same as ferritic designation), g ), and p precipitation p hardening g ((630 to 605). ) h Cast stainless steels are considered as another group. DIN designation of cast stainless steels is the same as that of the alloy steels only to be preceeded by the letter G to indicate casting: G-X12Cr 14, G-X10CrNi 18 8, G-NiMo 30, G X2NiCrMoCuN 25 20, G-X2NiCrMoCuN 20 etc. etc 29

Designation of HSLA Steels h Steels of very high strength are usually proprietary, and hence they are p byy the standard designations. g not specified h However, there are some special designations or trade names. ASTM classifies these steels into 6 groups based on their chemical composition and mechanical properties. SAE specifies 12 grades with emphasis on mechanical properties. h Followings are the examples of typical SAE and ASTM designations: Specification

Condition

SAE J410 C, ASTM A607

Semi-killed or killed

ASTM A606 (Type 2 and 4)

Improved corrosion resistance

ASTM 715 (sheet), ASTM A656 (plate) Inclusion controlled, improved formability, killed

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Designation of Super Alloys h Super alloys are designated by AISI 600 series with the specifications of high temperature and high strength: I. 601-604 : Martensitic low alloy II. 610-613 : Martensitic second hardening III. 614-619 : Martensitic chromium steels (616 is equivalent to X20CrMoWV 12 1) IV. 630-635 : Semiaustenitic and martensitic precipitation hardening stainless steels V 650-653 : Austenitic steels strengthened by cold/hot work V. VI. 660-665 : Austenitic super alloys (some of German equivalents are classified under “Aviation Standard”;; e.g. g No. 1.4944 for 660 and 1.4974 for 661))

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Designation by Mechanical Properties h Steels for general structural purposes are designated by mechanical properties by DIN, EURONORM and KARABÜK Demir Çelik (Turkey). h “St xx-y” xx y” is the DIN designation where “xx” is tensile strength and “y” is quality grade number denoting maximum contents of P and S: Symbol

Maximum Content

USt 37-1 (rimmed), RSt 37-1 (killed)

0.2% C, 0.07% P, 0.05% S

USt 37-2 ((rimmed), ), RSt 37-2 ((killed))

0.17-018% C, 0.05% P, 0.05% S

St 37-3 (RR specially killed)

0.17% C, 0.045% P, 0.045% S

USt 42-1, RSt 42-1

0.25% C, 0.08% P, 0.05% S

USt 42-2, RSt 42-2

0.23-0.25% C, 0.05% P, 0.05% S

St 42-3

0.23% C, 0.045% P, 0.045% S

RSt 46-2

0.2% C, 0.05% P, 0.05% S

St 46-3

0.2% C, 0.045% P, 0.045% S

h In Euronorm; Fe is substituted for symbol St, the letters (A-D) are used instead of quality numbers (1-3) (1 3) and the yield strength is used instead of tensile strength:

DIN

Euronorm

USt 34-1

Fe 34-A

RSt 34-2

Fe 34-B3FN

St 37-3

Fe 37-C3FN

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Designation of Cast Irons h It is not possible to specify cast iron by a standard chemical analysis. A single analysis of cast iron can produce entirely different types of iron, depending upon f foundry d practice, ti shape h and d size i off casting; ti allll off which hi h influence i fl cooling li rate. t Thus, iron is usually specified by mechanical properties. Designation of Gray CI:

Standard

Designation

h It is designated by its tensile strength. Some examples of standards and corresponding designations are shown (“xx” is the tensile strength):

TS 1111 (T (Turkish) ki h)

2) DDL – XX (kg/mm (k /

DIN 1691 (German)

GL – XX (kg/mm2)

ASTM A48 (American) (A i ) Class Cl – XX (lb/in (lb/i 2 x 1000) BS 1452 (British)

Grade – XX (MPa)

Designation of White CI: h Unlike gray CI, there are no specifications for white CI. h Symbols of “DDB” and “GGW” are used to designate white iron in short form by TS and DIN, respectively. 33

Designation of Cast Irons Designation of Ductile (Nodular) CI: h It is designated g by y three-letter abbreviation followed byy its tensile strength g ((“xx” in kg/mm2) such as “DDK-XX” in TS 1111 and “GGG-XX” in DIN 1693. h ASTM designation (A339-55 and A396-58) of a typical alloy is: “xx-yy-zz” where “xx” is the minimum tensile strength (in psi), “yy” is the minimum yield strength (in psi), and “zz” is the percentage of elongation over 20 inches gauge. Designation of Malleable CI: h It is designated as “DDTS-xx” and “DDTB-xx” in TS 1111 and “GTS-xx” and “GTW-xx” in DIN 1692 where “xx” is the minimum tensile strength. h ASTM designation d i ti i based is b d on 5-digit 5 di it system: t “ “xxxyy” ” where h “ “xxx” ” multiplied lti li d by 100 is the yield strength (in psi) and “yy” is % elongation over 2 inches gauge length g ((e.g. g “32510” means Sy y = 32500 p psi with 10% elongation). g )

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