BS 970 steels..Basic Notes on steels..... Sample specifications...... BS 970 numbering system explained...... Modernequivalents to BS 970 1955;EN numbers......Important Notes:1) BS 970 has been generally superseded by European based standards Notes on European Standards2) All information on this page has been interpreted from the relevent Standard, Books eg Newnes Mech. EngPocket Book, Kempe's, Other Web Sites, and Leaflets. This information is of a general nature for initialguidance. Selection of materials for use must be by communication with the suppliers and by reference to theappropriate codes - The best standards to use are the European EN based standards -

Basic Steel Selection Based on BS 970

Typical selection of steels and useful notes

STEEL NotesCarbon SteelBS 970230M07(EN1A)

A low carbon, free cutting, mild steel suitable for machining using automaticand CNC machines. Available as rolled or normalised in round, flat or hexagonform

BS 970070M20(EN3A)

A mild steel used for general purposes. Suitable for lightly stressed fasteners,shafts etc. Can be easily machined and welded. Available hot rolled,normalised, cold drawn or turned. Supplied in Black round or square , brightround square, flat and hexagon.

BS 970080M30(EN5/EN6)

A medium strength steel. Used to make, shafts, racks, pinions, studs, bolts,nuts, rollers, etc. Supplied as square bar, or round bar or flat.

BS 970080M40(EN8)

A medium strength steel. Suitable for stressed pins, shafts studs, keys etc.Available as rolled or normalised. Supplied as square bar, or round bar or flat.

BS 970070M55(EN9)

A hard wearing medium carbon steel which can be hardened. Available as hotrolled, normalised, Cold drawn or turned. Sections available black round, blacksquare, bright round and black flat.

BS 970080M15(EN32)

A case hardening mild steel suitable for general engineering applications.When case hardened results in a hard surface with a tough core. Used formaking gears cams and rollers etc. Supplied as black round bar and sections

Alloy SteelBS 970605M36

A manganese molydenum steel with good ductily and mechanical strength.Available in heat treated condition e.g (R,S,T).Supplied as black round or

(EN16) square bar and bright round or square, and hexagons.

BS 970709M40(EN19)

A 1% typical chromium molybdenum steel with higher molybdenum. Can beinduction hardened. Used for gears, and high strength shafts etc. Suitable forhigher strength applications when resistance to shock is required. Availableannealed. Supplied as black round or square bar and bright round or square,and hexagons.

BS 970817M40(EN24)

A nickel chromium molybdenum steel with high strength and toughness. Usedfor gears axles and high strength studs. Supplied as rolled, annealed andhardened and tempered. Supplied as black round or square bar and brightround or square, and hexagons

BS 970655M13(EN36)

A high quality nickel chromium case hardening steel. Can be hardened toprovide hard surface with a strong tough core. Used for high duty gears andshafts. Supplied in as-rolled condition in black square and round bar andbright round.

BS 970722M24(EN40B)

A 3% chromium molybdenum nitriding steel. Provide good tough corestrength with a hard nitrided surface for wear resistance. Supplied in as-rolled,annealed and hardened and tempered condition in black square and round bar.

Stainless SteelBS970416S21(EN56)

Martensitic (Magnetic), can be hardened and tempered to give improvedtensile strength. FM** grade. Typical applications include cutlery, surgicalinstruments, fasteners, valves, spindles and shafts.

BS 970431S29(EN57)

Martensitic (Magnetic). Supplied heat treated with a high tensile strength.Typical applications include cutlery, surgical instruments, fasteners, valves,spindles and shafts.

BS 970430S15typ (EN60)

Ferritic. Low Strength but good ductility. Used food processing and cateringequipment and automotive trim,car exhaust systems etc.

BS 970Grade304S15(EN58-)

Austenitic (Non-Magnetic)Cannot be heat treated but work hardens. Readilyformed and welded,used mainly in domestic, dairy and decorative appliancesgeneral purpose grade for corrosion resistant applications. This grade is themost widely used of all stainless steels. Its chemical composition,provide thebest all-round performance S.S. at relatively low cost. It has excellent lowtemperature properties. Lower Carbon grades (S15 and less) have improvedweldability.

BS 970Grade316S16(EN58J)

Austenitic (Non-Magnetic)Cannot be heat treated but work hardens. It offershigh resistance to corrosion. Generally machined components and pipefittings. This grade is almost as popular as the 304 grade the increased Mocontent makes the steel more suitable for resisting pitting and crevice then304 Grade. Lower Carbon grades (S15 and less) have improved weldability.

BS 970Grade321S12(EN58B-C)

Austenitic (Non-Magnetic)Cannot be heat treated but work hardens.Titanium stabilized, which offers improved welding properties.

BS 970Grade310S31

Austenitic (Non-Magnetic). Pocesses good resistance to scaling at hightemperatures. For continuous high temperature service in the range 850 -1000oC.

Sample Steels SpecificationsTypical steels with general specifications notes

Important Note:The values below are not comprehensive and must be used with extreme care.The strength values e.g. the proof stress and yield stress, reduce as the section increases. In the tables belowthe relevant sections are often thin and so the strength values are maximum values. Please refer to the relevantstandards for important work..

Type Of Steel BS SpecBS 970Composition %C-Mn-Ni-Cr-Mo Condition

YieldStress x106 Pa

TensileStress MPa

Elongation%

Low Carbon Steel 230M07 0,15C% 1,1%Mn Hot rolled 215 360 21Low Carbon Steel 230M07 0,15C% 1,1%Mn HR -> CD(thin) 340 480 6Low Carbon Steel 070M20 0,2C% 0,7%Mn Normalised 215 430 21Low Carbon Steel 070M20 0,2C% 0,7%Mn HR->CD(thin) 440 560 10ConstructuralSteel 080M40 0,4%C 0,8%Mn Normalised 280 550 16ConstructuralSteel 080M40 0,4%C 0,8%Mn

HR -> CD(thin) 530 660 7

Low Manganese 150M28 0,28%C 1,5%Mn HeatTreat(P) 355 587 20

Nickel Manganese 503M40 0,4%C -0,9%Mn 1,0%Cr HeatTreat(R) 525 700 min 17ManganeseMolybdenum 608M38 0,38%C 1,5%Mn 0,5%Mo Heat Treat 1000 1130 19

Nickel Chromium 633M31 0,31%C 0,60%Mn 3,0%Ni1,0%CrHeatTreat(U) 755 927 23

Nickel-Chrom-Mo 817M40

0,4%C 0,55%Mn 1,2%Cr0,3%Mo

Heat Treat(W) 940 1075 11

Nickel-Chrom-Mo 835M30

0,3%C 0,55%Mn 4,25%Ni1,25%Cr 0,3%Mo

Hard'n+Temp 1470 1700 14

Mang-Ni-Chr-Mo 945M38 0,38%C 1,4%Mn 0,75%Ni0,5%Cr 0,20%MoHeat Treat(V) 850 1040 2

Steel Ferritic 403S17 0,08%C 1,0%Mn 13%Cr0,5%Ni Softened 280 420 20StainlessMartensitic 420S45 0,3%C 0,5%Mn 13,0%Cr

Heat Treat(R) 525 700 15

18/8 StainlessAustenitic 302S25

0,12%C 0,8%Mn 8,5%Ni18,0%Cr Softened 278 618 50

18/8 StainlessAustenitic 302S25

0,12%C 0,8%MN 8,5%Ni18,0%Cr Cold work 803 896 30

18/8 St. (No WeldDecay) 321S20

0,05%C 0,8%Mn 8,5%Ni18,0%Cr 1,6Ti Softened 278 649 45

18/8 St. (No WeldDecay) 321S20

0,05C 0,8%Mn 8,5%Ni18,0%Cr 1,6Ti Cold Worked 402 803 30

BS970 Numbering system explainedThe BS970 code number is constructed as follows;a) The first three symbols are a number code indicating the type of steel:000 to 199 Carbon and carbon-manganese steels. The number represents the manganese content x 100200 to 240 Free cutting steels. The second and third number indicate the sulphur content x 100250 Silicon Manganese valve steels300 to 499 Stainless and heat resisting steels500 to 999 Alloy Steels

b) The fourth symbol is a letter code .A The steel is supplied to a chemical compostion determine by analysis of the batch sample.H The steel is supplied to a hardenability specificationM The steel is supplied to a Mechanical Property specification.

S The steel is a stainless steel

c) The fifth and sixth symbol is a number is the actual mean carbon content x 100

In addition to the above coding a condition coding may be applied. indicating the tensile strength range afterheat treatment. This is used in conjunction with a limiting section designation. (See table below)

Condition Code Letter Tensile Strength (Mpa)Min MaxP 550 700Q 620 770R 700 850S 770 930T 850 1000U 930 1080V 1000 1150W 1080 1240X 1150 1300Y 1240 1400Z 1540 -

Table of BS 970: 1955 EN equivalents* Steel No Relate to European Numbering system BS EN 10027-2 - I will add numbers as I locate themBS970 1955 EN steel EquivalentEN No BS 970 Name Note. * Steel No1A 230M07 Low CarbonFree Cutting C 1.0715

1B 240M07 Low CarbonFree Cutting C -3A 070M20 '20' C 1.04025 080M30 '30' C 1.1178/1.11795A 080A27 '30' C 5B 080A30 '30' C 1.05288 080M40 '40'C 1.0503/1.0511

BS970 1955 EN steel EquivalentEN No BS 970 Name Note. *Steel No39A 659M15 4.0% Ni/Cr 34 665M17 35A 665A22 1.5% Ni/Mo 35 665M23 1.5% Ni/Mo 35B 665A24 1.5% Ni/Mo 361 805M17 0.5% Ni/Cr/Mo 362 805M20 0.5% Ni/Cr/Mo 363 805M25 0.5% Ni/Cr/Mo 353 815M27 1.5% Ni/Cr/Mo

8A 080A35 '35'C 8B 080A37 '37'C 8C 080A40 '40'C 1.11868D 080A42 '42'C 9 070M55 '50'C 1.1209/1.053543A 080A50 '50'C 1,120643B 080A47 '47'C 43C 080A52 '52'C 43D 080A62 '62'C 1.122143E 080A67 '67'C 1A 220M07 Low CarbonFC**

1B 240M07 Low CarbonFC** 8M 212M36 '36' C FC** 1.072615AM 216M36 '36' C' FC** 8BM 212A37 '37' C FC** 8DM 212M44 '42' C FC** ?1.07278M 212M44 '44' C FC** 12 503M40 1% Ni 12B 503A37 1% Ni 12C 503A42 1% Ni 11 526M60 1% Cr 18 530M40 1% Cr 1.703518A 530A30 1% Cr 1.840118B 530A32 1% Cr 1.703318C 530A36 1% Cr 18D 530A40 1% Cr 1.703531 534A99 1.5% Cr 31 535A99 1.5% Cr

16D 605M301.5% Mn/Mo(WaterHardening)

16 605M36 1.0% Mn/Mo 1.700616B 605A32 1.0% Mn/Mo 16C 605A37 1.0% Mn/Mo 1.5432

354 820M27 1.75%Ni/Cr/Mo 355 822M17 2.0% Ni/Cr/Mo 36C 832M13 3.0% Ni/Cr/Mo 1.6657351 635M15 0.75% Ni/Cr 352 637M17 1% Ni/Cr 36A 655M13 3.25% Ni/Cr 39A 659M15 4.0% Ni/Cr 34 665M17 1.75% Ni/Mo 35 665M23 1.75% Ni/Mo 361 805M17 0.5% Ni/Cr/Mo 362 805M20 0.5% Ni/Cr/Mo 1.6522'3363 805M25 0.5% Ni/Cr/Mo 353 815M17 1.5% Ni/Cr/Mo 354 820M17 1.75%Ni/Cr/Mo 355 822M17 2.0% Ni/Cr/Mo 36C 832M13 3.5% Ni/Cr/Mo 1.665739B 835M15 4.0% Ni/Cr/Mo 43 080A22 '52'Carbon 43E 080A67 '67'Carbon 42 070A72 '52'Carbon 44 060A96 '96'Carbon 1.1274

45 250A53Silico-Manganese'53'Carbon

1.0904

45A 250A58 '58'Carbon 45A 250A61 '61'Carbon 47 735A50 1.0% Cr 1.815948 527A60 0.75% Cr/Va Stainless Steels58A 302S25 CrNi 18/9 C0,12 ..Aust 1.4828

58M 303S41CrNi 18/9 SbearingFM**..Aust

58E 304S15 CrNi 18/19 C0,06 ..Aust 1.4301

16M 605A32 1.5%Mn/Mo(FC**) 111 640M40 1.25% Ni/Cr 111A 640M40 1.25% Ni/Cr 23 653M31 3.0% Ni/Cr 19A 708M40 1.0% Cr/Mo 1.722319B 708A37 1.0% Cr/Mo 1.722019C 708A42 1.0% Cr/Mo 19 709M40 1.0% Cr/Mo(Higher Mo) 1.7225

40B 722M24 3.0% Cr/Mo(Nitriding) 1.736113 785M19 1.5% Mn/Ni/Mo 110 816M40 1.0% Ni/Cr/Mo(Low Mo) 1.658224 817M40 1.0% Ni/Cr/Mo 1.6582/1.656525 826M31 2.5% Ni/Cr/Mo(Medium C)

26 826M40 2.5% Ni/Cr/Mo(High C) 1,674627 830M31 3.0% Ni/Cr/Mo 30B 835M30 4.0% Ni/Cr/Mo 1.6747

40C 897M393.25%Ni/Cr/Mo/Va(Nitriding)

41A 905M311.5% Cr/Al/Mo(Nitriding)(Medium C)

1.8509

41B 905M391.5% Cr/Al/Mo(Nitriding)(HighC)

100 945M38 1.5% Mn/Ni/Cr/Al/Mo

100C 945A40 1.5% Mn/Ni/Cr/Al/Mo 1.6546351 635M15 0.75% Ni/Cr 352 637M14 1.0% Ni/Cr 36A 655M13 3.25% Ni/Cr 1.575236A 655M13 3.25% Ni/Cr 1.5752

58H 315S16CrNiMo17/10/1,5 C 0,07..Aust

58J 316S16CrNiMo17/11/2,5 C 0,07..Aust

1.4401

58J 316S17CrNiMo17/12/2,5 +Ti C0,08 ..Aust

1.4401

58B/58C 321S12 CrNi 18/9 +Ti C0,08 ..Aust 1.4541

58B/58C 321S20 CrNi 18/9 +Ti C0,12 ..Aust

58M 325S21 CrNi 18/9 +Ti+S FM** ..Aust 1.4305

54 331S40 NiCrW14/14/2,5..Valve

54A 331S42NiCrW14/14/2,5 + Mo..Valve

58F/58G 347S17 Cr/Ni 18/9/Nb/C0,08 ..Aus 1.455052 401S45 Si/Cr 3/8 ..Valve 56A 410S21 13CrC0,12Mart 1.4006

56AM 416S21 13Cr C 0,12 SFM** ..Mart 1.4005

56AM 416S41 13Cr C 0,12 SeFM** ..Mart

56BM 416S29 13Cr C 0,17 SFM** ..Mart

56C 416S3713Cr C 0,24 Sbearing FM**..Mart

56B 420S29 13Cr C0,17..Mart 1.4024

56C 420S37 13Cr C 0,24..Mart 1.4021

56D 420S45 13Cr C0,32..Mart 1.4028

60 430S15 17Cr C0,10....Fer 1.4016

57 431S29 17Cr 2,5NI C0,10....Mart 1.4057

59 443S65 CrNiSi20,1.5,2..Valve

Stainless Steels ...Aus = Austenitic, Mart = Martensitic, Fe = Ferritic. FC** = Free Cutting..FM** = Free machining

Relevant Steel LinksBritish Stainless Steel Association ..Properties /Relevant Standards for Stainless Steels1.Plymouth College ..Notes On Steels2.Grade Alternatives... Mikra metal Stainless Steel Grades3.Material Cross Reference List..Coromant- Sandvik Comprehensive list of steels4.Australian Stainless Steel Development Agency ..Contains physical and mechanical properties5.Key-To-Steel ..An excellent reference site for steel classifications and properties.- registration requiredfor full access

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Casti Metals Black Book ..Download Document. A comprehensive reference text on european metalsincluding Ref to latest Standards

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