© ISO 2014 Heat treated steels, alloy steels and free cutting steels — Part 17 Ball and roller bearing steels Aciers pour traitement thermique, aciers alliés et aciers pour décolletage — Partie 17 Aci[.]
Classification
The classification of the relevant steel grades is allocated in accordance with ISO 4948-1 and ISO 4948-2 All steel grades covered by this part of ISO 683 are special steels.
Designation
For the steel grades covered by this part of ISO 683, the steel names given in the relevant tables are allocated in accordance with ISO/TS 4949.
5 Information to be supplied by the purchaser
Mandatory information
The manufacturer shall obtain the following information from the purchaser at the time of enquiry and order: a) the quantity to be delivered; b) the designation of the products form (billets, bars, rod, wire, tubes, rings, discs, etc.); c) either the reference to the dimensional standard and the dimensions and tolerances selected from it (see 7.6) or the designation of any other document covering the dimensions and tolerances required for the product; d) a reference to this part of ISO 683, i.e ISO 683-17; e) the designation of the steel grade (see Table 3); f) the symbol for the heat-treatment condition on delivery (see 6.3.1 and Table 1); g) usually designation for an inspection certificate 3.1 or, if required, an inspection certificate 3.2 in accordance with ISO 10474.
Options/Supplementary or special requirements
A number of options are specified in this part of ISO 683 and listed below If the purchaser does not indicate the wish to implement any of theses options, the products will be supplied in accordance with the basic specifications of this part of ISO 683 (see 5.1). a) If another surface condition than ‘hot-worked’ or a special surface quality is required, the surface condition (see Table 2), and the surface quality (see 7.5). b) Any requirement concerning the hardenability (+H) (see 7.1.3 and Table 5) and the verification of hardenability and if agreed the information about calculation of the hardenability (see 9.2.2). c) Any supplementary requirement that shall be complied with, the symbol and, where necessary, the details of this supplementary requirement (see Annex A).
EXAMPLE 50 hot-rolled round bars according to ISO 1035-1 with nominal diameter of 50,0 mm, nominal length of 8 000 mm and with tolerance class S on diameter of ± 0,40 mm and tolerance class L2 on length of +100/0 mm in accordance with ISO 1035-4 and with hot-worked surface made of steel grade ISO 683-17, 100Cr6 (see Table 3) in annealed condition to achieve spheroidized carbides (+AC), with an inspection certificate 3.1 in accordance with ISO 10474:
50 round bars ISO 1035-1/-4 – 50,0 S × 8 000 L2 steel grade ISO 683-17 - 100Cr6+AC inspection certificate ISO 10474 - 3.1
General
With the restrictions given by the requirements in 6.2 and 6.3 the manufacturing process of the steel and of the products is left to the discretions of the manufacturer.
If requested, the purchaser shall be informed about the steel making process used.
Remelting of the steel may be agreed upon at the time of enquiry and order.
Deoxidation
All steels shall be deoxidized.
Heat treatment and surface condition at delivery
The products shall be delivered in one of the heat-treatment conditions given in Table 1, lines 2 to 10, as agreed at the time of enquiry and order If there is no agreement, the products shall be delivered in the untreated condition.
If agreed upon at the time of enquiry and order, the products shall be delivered in one of the particular surface conditions given in Table 2, lines 3 to 9.
Each product shall be traceable to the cast, see Clause 10.
Chemical composition and hardenability
Table 1 gives a survey of combinations of usual heat-treatment conditions at delivery, product forms and requirements according to Tables 3 to 6 (chemical composition, hardenability, maximum hardness, hardness range).
The chemical composition determined by cast analysis shall comply with the values in Table 3.
Permissible deviations between the limiting values for cast analysis and the values for product analysis are given in Table 4.
The product analysis shall be carried out when specified at the time of the enquiry and order (see 9.1 and A.2).
Where the steel is not ordered according to hardenability requirements, i.e where the steel type designations of Table 3 and not the designations given in Table 5 are applied, the requirements for hardness specified in Table 6 (see also Table 1, column 9) apply, as appropriate, for the particular heat- treatment condition In this case, the values of hardenability given in Table 5 are for guidance purposes only.
Where the steel is ordered to hardenability requirements by using the designations given in Table 5 the values of hardenability given in Table 5 apply in addition to the requirements cited in Table 1, column 9 (see footnote b to Table 3).
The hardness in the usual conditions of delivery is given in Table 6.
Microstructure
7.2.1 Austenitic grain size of case-hardening and induction-hardening bearing steels
Case-hardening steels and induction-hardening steels shall have a fine grain size of 5 or finer (see ISO 643) For verification of the grain size, see A.3.
7.2.2 Spheroidization and distribution of carbides
7.2.2.1 For deliveries in treatment conditions +AC and +AC+C, the carbides of the through-hardening steels shall be spheroidized and the carbides of the stainless and high-temperature bearing steels shall be predominantly spheroidized Case-hardening steels may show remnants of incompletely spheroidized carbides For the degree of spheroidization see A.4.
7.2.2.2 For distribution of carbides, see A.5.
7.2.3 Structure of case-hardening steels in the condition +FP
The structure shall consist of ferrite-pearlite Bainite contents up to 10 % are, however, permissible.
Non-metallic inclusions
The characterization of non-metallic inclusions is critically important to the fatigue life of bearings Therefore all bearing steels shall have a certain degree of cleanliness The requirements for the content of non-metallic inclusions apply in every case; however, verification requires a special agreement, see A.6.
If verification is agreed then the method and acceptance limits shall be agreed at the time of enquiry and order.
Internal soundness
Where appropriate, requirements relating to the internal soundness of the products shall be agreed at the time of enquiry and order, see A.7.
Surface quality
7.5.1 All products shall have a smooth surface finish appropriate to the manufacturing process applied.
7.5.2 Ground or peeled/turned or machined products shall be free from surface discontinuities detrimental to practical use and surface decarburization.
7.5.3 If hot-rolled, forged, cold-reduced or rough-machined products are ordered for peeling or grinding to avoid a) surface decarburization, and b) surface defects the machining allowances shall be agreed upon at the time of enquiry and order.
Alternatively, for round bars and rod, the permissible depth of surface discontinuities may be specified in accordance with ISO 9443.
Shape, dimensions and tolerances
The shape, dimensions and tolerances of the products shall comply with the requirements agreed upon at the time of enquiry and order The agreements shall, as far as possible, be based on corresponding International Standards (see Annex C) or, otherwise, on suitable national standards.
Testing procedures and types of inspection documents
8.1.1 Products complying with this part of ISO 683 shall be ordered and delivered with inspection certificate 3.1 or 3.2 as specified in ISO 10474 The type of document shall be agreed upon at the time of enquiry and order If the order does not contain any specification of this type, an inspection certificate 3.1 shall be issued.
8.1.2 The specific inspections and tests described in 8.2 and 8.3 shall be carried out and the results shall be confirmed in the inspection certificate.
In addition the inspection certificate report shall cover: a) confirmation that the material complies with the requirements of the order; b) results of the cast analysis for all elements specified in Table 3 for the steel grade concerned;c) the results of all inspections and tests ordered by supplementary requirements (see Annex A);d) the symbol letters or numbers connecting the inspection document with the relevant test unit.
Frequency of testing
The amount of testing, the sampling conditions and the test methods to be applied for the verification of the requirements shall be in accordance with the prescriptions in Table 7.
Specific inspection and testing
8.3.1 Verification of the hardenability and hardness
The hardness requirements given for the relevant heat-treatment condition in Table 6 (see also Table 1, column 9, sub-column 9.2) shall be verified.
For steels ordered with the symbol +H in the designation (see Table 5), in addition, the hardenability requirements according to Table 5 shall be verified.
8.3.2 Inspection of the surface quality
Unless otherwise agreed at the time of enquiry and order (see A.8), the extend of testing and the test method is left to the discretion of the manufacturer.
Unless otherwise agreed at the time of enquiry and order (see A.9), the number of products to be inspected for their shape and dimensions shall be left to the discretion of the manufacturer.
Chemical analysis
The choice of a suitable physical or chemical analytical method for the analysis shall be at the discretion of the manufacturer In cases of dispute, the method for product analysis used shall be agreed, taking into account the relevant existing International Standards.
NOTE The list of available International Standards on chemical analysis is given in ISO/TR 9769.
Hardness and hardenability tests
For products in treatment conditions +S, +A, +TH, +AC, +AC+C and +FP (see Table 6), the hardness shall be measured in accordance with ISO 6506-1.
As far as available, the manufacturer has the option to verify the hardenability by calculation The calculation method is left to the discretion of the manufacturer If agreed at the time of enquiry and order the manufacturer shall give sufficient information about the calculation for the customer to confirm the result.
If a calculation formula is not available or in the case of dispute, an end-quench hardenability test shall be carried out in accordance with ISO 642 The temperature for quenching shall comply with Table 5 The hardness values shall be determined in accordance with ISO 6508-1, scale C.
For retests, ISO 404 shall apply.
The manufacturer shall mark the products or the bundles or boxes containing the products in a suitable way, so that identification of the cast, the steel grade and the origin of the delivery is possible (see A.10).
Table 1 — Combination of usual heat-treatment conditions at delivery, product forms and requirements according to Tables 3 to 6 1 2 3 4 5 6 7 8 9 10 1 H ea t-t re at m en t c on di tio n a t de live ry Sy m bo l X = Ap pl ic ab le f or Ap pl ic ab le r eq ui re m en ts i f t he s te el i s o rd er ed w ith t he d es ig na tio n g iv en in Ta bl es 3 , 4 a nd 6 Ta bl e 5 bil le ts ba rs w ir e rod w ire tub e ri ng s an d di sc s 9 1 9 2 10 1 10 2 10 3 2 Un tr ea te d N one or +U x x x – – – Ch em ical co mp os iti on ac co rd in g t o Ta bl es 3 a nd 4
- 3 Tr ea te d f or c ol d s he ar ab ili ty +S x x x – – – M ax imu m ha rd ne ss or h ar d- ne ss r an ge ac co r- di ng t o Ta bl e 6
Co lu m n + S As i n c ol um n 9 1 a nd 9 2 (s ee fo ot no te b t o Ta bl e 3 )
Ha rd en ab ilit y va lu es a cc or di ng to Ta bl e 5
4 So ft a nne al ed /s olu tion a nne al ed +A /+A T – x x – – – Co lu m n + A 5 Tr ea te d t o h ar dn es s r an ge +T H – x x x - x Co lu m n +T H 6 An ne al ed t o a ch ie ve s ph er oi di ze d ca rb id es +A C – x x x x x Co lu m n +A C 7 An ne al ed t o a ch ie ve s ph er oi di ze d ca rb id es a nd c ol d- w or ke d +A C+ C – x – x x x Co lu m n +A C+ C 8 Is ot he rm ic al ly t re at ed t o f er ri te - pe rl ite s tr uc tu re a nd h ar dn es s ra nge +F P – x x – x x Co lu m n +F P 9 St re ss re lie ve d +S R – – – x x – – 10 O the rs O th er t re at m en t c on di tio ns , e g t he q ue nc he d a nd t emp er ed c on di tio n, m ay b e a gr ee d a t t he t im e o f e nq ui ry a nd o rd er
Table 2 — Surface condition at delivery 1 2 3 4 5 6 7 8 9 Su rf ac e c on di tio n a t d el iv er y Sy m bo l x = In g en er al a pp lic ab le f or bil le ts ba rs w ir e r od a w ir e a tub es ri ng s a nd di sc s Un le ss o th er w is e a gr ee d As -h ot -w or ke d N on e o r + H W x x x – x x rt ic ul ar c on di tion s s up - pl ie d b y a gr ee m en t
M ac hi ne d +M A – x – – – x Pee le d/ tu rn ed +S H – x x – x – Gr ou nd +G – x – – – – Co ld dra w n +C – x – x x – Col d p ilg er ed ( ro ck ed ) +C P – – – – x – Co ld ro lle d +C R – – – – – x O the rs – – x x x x x ra w n r od i s b y d ef in iti on w ir e ( se e I SO 6 92 9)
Table 3 — Steel grades and chemical composition (cast analysis) St ee l d es ig na ti on % [ m as s f ra ct io n] a, b N ame C Si Mn P S Cr Mo Ni V W O the rs Th ro ug h- ha rd en ing be ar ing s te el s 10 0C r6 0, 93 t o 1 ,0 5 c 0, 15 t o 0 ,3 5 d 0, 25 t o 0 ,4 5 0, 02 5 0, 01 5 e 1, 35 t o 1 ,6 0 0, 10 – – – Al : 0 ,0 50 Ca : f Cu : 0 ,3 0 O: 0 ,0 01 5 g Ti: h
10 0C rM nS i4 –4 0, 93 t o 1 ,0 5 c 0, 45 t o 0 ,7 5 0, 90 t o 1 ,2 0 0, 02 5 0, 01 5 e 0, 90 t o 1 ,2 0 0, 10 – – – 10 0C rM nS i6 –4 0, 93 t o 1 ,0 5 c 0, 45 t o 0 ,7 5 1, 00 t o 1 ,2 0 0, 02 5 0, 01 5 e 1, 40 t o 1 ,6 5 0, 10 – – – 10 0C rM nS i6 –6 0, 93 t o 1 ,0 5 c 0, 45 t o 0 ,7 5 1, 40 t o 1 ,7 0 0, 02 5 0, 01 5 e 1, 40 t o 1 ,6 5 0, 10 – – – 10 0C rM o7 0, 93 t o 1 ,0 5 c 0, 15 t o 0 ,4 5 0, 25 t o 0 ,4 5 0, 02 5 0, 01 5 e 1, 65 t o 1 ,9 5 0, 15 t o 0 ,3 0 – – – 10 0C rMo 7–3 0, 93 t o 1 ,0 5 c 0, 15 t o 0 ,4 5 0, 60 t o 0 ,8 0 0, 02 5 0, 01 5 e 1, 65 t o 1 ,9 5 0, 20 t o 0 ,3 5 – – – 10 0C rM o7 –4 0, 93 t o 1 ,0 5 c 0, 15 t o 0 ,3 5 0, 60 t o 0 ,8 0 0, 02 5 0, 01 5 e 1, 65 t o 1 ,9 5 0, 40 t o 0 ,5 0 – – – 10 0C rM nM oS i8 –4 -6 0, 93 t o 1 ,0 5 c 0, 40 t o 0 ,6 0 0, 80 t o 1 ,1 0 0, 02 5 0, 01 5 e 1, 80 t o 2 ,0 5 0, 50 t o 0 ,6 0 – – – Ca se -h ar de ni ng be ar ing s te el s 20 Cr 3 0, 17 t o 0 ,2 3 0,4 0 0, 60 t o 1 ,0 0 0, 02 5 0, 01 5 e 0, 60 t o 1 ,0 0 – – – – Al : 0 ,0 50 Ca : f Cu : 0 ,3 0 O: 0 ,0 02 0 g Ti: h
20 Cr 4 0, 17 t o 0 ,2 3 0,4 0 0, 60 t o 0 ,9 0 0, 02 5 0, 01 5 e 0, 90 t o 1 ,2 0 – – – – 20 M nC r4 –2 0, 17 t o 0 ,2 3 0,4 0 0, 65 t o 1 ,1 0 0, 02 5 0, 01 5 e 0, 40 t o 0 ,7 5 – – – – 17 M nC r5 0, 14 t o 0 ,1 9 0,4 0 1, 00 t o 1 ,3 0 0, 02 5 0, 01 5 e 0, 80 t o 1 ,1 0 – – – – 19 M nC r5 0, 17 t o 0 ,2 2 0,4 0 1, 10 t o 1 ,4 0 0, 02 5 0, 01 5 e 1, 00 t o 1 ,3 0 – – – – 15 Cr M o4 0, 12 t o 0 ,1 8 0,4 0 0, 60 t o 0 ,9 0 0, 02 5 0, 01 5 e 0, 90 t o 1 ,2 0 0, 15 t o 0 ,2 5 – – – 20 Cr M o4 0, 17 t o 0 ,2 3 0,4 0 0, 60 t o 0 ,9 0 0, 02 5 0, 01 5 e 0, 90 t o 1 ,2 0 0, 15 t o 0 ,2 5 – – – 20 M nC rM o4 –2 0, 17 t o 0 ,2 3 0,4 0 0, 65 t o 1 ,1 0 0, 02 5 0, 01 5 e 0, 40 t o 0 ,7 5 0, 10 t o 0 ,2 0 – – – 20 M nN iC rM o3 –2 0, 17 t o 0 ,2 3 0,4 0 0, 60 t o 0 ,9 5 0, 02 5 0, 01 5 e 0, 35 t o 0 ,7 0 0, 15 t o 0 ,2 5 0, 40 t o 0 ,7 0 – – 20 Ni Cr M o7 0, 17 t o 0 ,2 3 0,4 0 0, 40 t o 0 ,7 0 0, 02 5 0, 01 5 e 0, 35 t o 0 ,6 5 0, 20 t o 0 ,3 0 1, 60 t o 2 ,0 0 – – 18 Cr Ni M o7 –6 0, 15 t o 0 ,2 1 0,4 0 0, 50 t o 0 ,9 0 0, 02 5 0, 01 5 e 1, 50 t o 1 ,8 0 0, 25 t o 0 ,3 5 1, 40 t o 1 ,7 0 – – 18 Ni Cr M o1 4– 6 0, 15 t o 0 ,2 0 0,4 0 0, 40 t o 0 ,7 0 0, 02 5 0, 01 5 e 1, 30 t o 1 ,6 0 0, 15 t o 0 ,2 5 3, 25 t o 3 ,7 5 – – 16 Ni Cr M o16 –5 0, 14 t o 0 ,1 8 0,4 0 0, 25 t o 0 ,5 5 0, 02 5 0, 01 5 e 1, 00 t o 1 ,4 0 0, 20 t o 0 ,3 0 3, 80 t o 4 ,3 – –
Table 3 — (continued) ig na ti on % [ m as s f ra ct io n] a, b C Si Mn P S Cr Mo Ni V W O the rs In du ct ion- ha rde ni ng b ea ri ng s te el s 0, 52 t o 0 ,6 0 0,4 0 0, 60 t o 0 ,9 0 0, 02 5 0, 01 5 e – – – – – Al : 0 ,0 50 0, 52 t o 0 ,6 0 0,4 0 0, 90 t o 1 ,2 0 0, 02 5 0, 01 5 e – – – – – Ca : f , C u: 0 ,3 0 0, 65 t o 0 ,7 5 0,4 0 0, 80 t o 1 ,1 0 0, 02 5 0, 01 5 e – – – – – O: 0 ,0 02 0 g 0, 40 t o 0 ,4 6 0,4 0 0, 60 t o 0 ,9 0 0, 02 5 0, 01 5 e 0, 90 t o 1 ,2 0 0, 15 t o 0 ,3 0 – – – Ti : h St ai nl es s b ea ri ng s te el s 0, 43 t o 0 ,5 0 1, 00 1, 00 0, 04 0 0, 01 5 e 12 ,5 t o 1 4, 5 – – – – – 0, 60 t o 0 ,7 0 1, 00 1, 00 0, 04 0 0, 01 5 e 12 ,5 t o 1 4, 5 0,7 5 – – – – o1 7 0, 95 t o 1 ,2 0 1, 00 1, 00 0, 04 0 0, 01 5 e 16 ,0 t o 1 8, 0 0, 40 t o 0 ,8 0 – – – – N1 6–2 0, 37 t o 0 ,4 5 0, 60 0, 60 0, 02 5 0, 01 5 e 15 ,0 t o 1 6, 5 1, 50 t o 1 ,9 0 0, 30 0, 20 t o 0 ,4 0 – N: 0 ,1 6 t o 0 ,2 5 18 –1 0, 85 t o 0 ,9 5 1, 00 1, 00 0, 04 0 0, 01 5 e 17 ,0 t o 1 9, 0 0, 90 t o 1 ,3 0 – 0, 07 t o 0 ,1 2 – –
Table 3 — (continued) St ee l d es ig na ti on % [ m as s f ra ct io n] a, b N ame C Si Mn P S Cr Mo Ni V W O the rs H ig h-t emp er at ur e b ea ri ng s te el s 33C rMo V1 2– 9 0, 29 t o 0 ,36 0, 10 t o 0 ,4 0 0, 40 t o 0 ,7 0 0, 02 5 0, 01 5 2, 80 t o 3 ,3 0 0, 70 t o 1 ,2 0 0, 30 0, 15 t o 0 ,2 5 – Cu : 0 ,1 0 80 M oC rV 42 –1 6 0, 77 t o 0 ,8 5 0,4 0 0, 15 t o 0 ,3 5 0, 02 5 i 0, 01 5 i 3, 9 t o 4 ,3 4, 0 t o 4 ,5 – 0, 90 t o 1 ,1 0 0, 25 Cu : 0 ,3 0 13 M oC rN i4 2–1 6–1 4 0, 10 t o 0 ,1 5 0, 10 t o 0 ,2 5 0, 15 t o 0 ,3 5 0, 01 5 0, 01 0 3, 9 t o 4 ,3 4, 0 t o 4 ,5 3, 20 t o 3 ,6 0 1, 00 t o 1 ,3 0 0,1 5 Cu : 0 ,1 0 k X8 2W M oC rV 6– 5- 4 0, 78 t o 0 ,8 6 0,4 0 0,4 0 0, 02 5 0, 01 5 3, 9 t o 4 ,3 4, 7 t o 5 ,2 – 1, 70 t o 2 ,0 0 6, 0 t o 6 ,7 Cu : 0 ,3 0 X7 5W Cr V1 8– 4-1 0, 70 t o 0 ,8 0 0,4 0 0,4 0 0, 02 5 0, 01 5 3, 9 t o 4 ,3 0, 60 – 1, 00 t o 1 ,2 5 17 ,5 t o 1 9, 0 Cu : 0 ,3 0 El em en ts n ot q uo te d s ha ll n ot b e i nt en tio na lly a dd ed t o t he s te el w ith ou t t he a gr ee m en t o f t he p ur ch as er , o th er t ha n f or t he p ur po se o f f in is hi ng t he h ea t A ll r ea so na bl e p re ca u - tio ns s ho ul d b e t ak en t o p re ve nt a dd iti on s f ro m s cr ap o r o th er m at er ia ls , u se d i n t he m an uf ac tu re o f s uc h e le m en ts , w hi ch a ffe ct t he h ar de na bi lit y, m ec ha ni ca l p rop er tie s a nd app lic abi lit y a M ax im um v al ue s u nl es s o th er w is e i nd ic at ed b In th e ca se of th e gr ad es w ith sp ec ifi ed ha rd en ab ili ty re qu ir em en ts (s ee Ta bl e 5 ), ex ce pt fo r p ho sp ho ru s a nd su lfu r, in si gn ifi ca nt de vi at io ns fr om th e lim its fo r c as t a na ly si s a re pe rm is si bl e; t he se d ev ia tio ns s ha ll, h owe ve r, n ot e xc ee d ± 0, 01 % i n t he c as e o f c ar bo n a nd i n a ll o th er c as es t he v al ue s a cc or di ng t o Ta bl e 4 c M in im um l im its l owe r t ha n 0 ,9 3 % C or m ax im um l im its h ig he r t ha n 1 ,0 5 % C m ay b e a gr ee d u po n a t t he t im e o f e nq ui ry a nd o rd er d By a gr ee m en t m ax 0 ,1 5 % S i f or c ol d f or m in g e W he re m ac hi na bi lit y i s o f p ri m ar y i mp or ta nc e, m ax 0 ,0 30 % s ul fu r m ay b e a gr ee d a t t he t im e o f e nq ui ry a nd o rd er f In te nt io na l a dd iti on s o f c al ci um o r c al ci um a llo ys f or d eo xi da tio n o r i nc lu si on s ha pe c on tr ol a re n ot p er m it te d u nl es s s pe ci fic al ly a pp ro ve d b y t he p ur ch as er g Th e o xy ge n c on te nt a pp lie s t o c as t a na ly si s o r p ro du ct a na ly si s a t t he d is cr et io n o f t he m an uf ac tu re r h A m ax im um t ita ni um c on te nt m ay b e a gr ee d u po n a t t he t im e o f e nq ui ry a nd o rd er i M ax 0 ,0 15 % p ho sp ho ru s a nd m ax 0 ,0 08 % s ul fu r m ay b e a gr ee d u po n a t t he t im e o f e nq ui ry a nd o rd er k M ax 0 ,2 0 % C u m ay b e a gr ee d u po n a t t he t im e o f e nq ui ry a nd o rd er
Table 4 — Permissible deviations between the product analysis and the limiting values given in Table 3 for the cast analysis
Permissible maximum content according to cast analysis
Permissible deviation a , for all bearing steels
Cu Cu ≤ 0,30 + 0,03 a ± means that in one cast the deviation may occur over the upper value or under the lower value of the specified range in Table 3, but not both at the same time. b For stainless bearing steels: Mn +0,03 %. c For high-temperature bearing steels: Mo +0,03 %.
Table 5 — Hardness limits for case-hardening and induction-hardening steels (+H-grades) in the end-quench hardenability test St ee l d es ig na ti on Li m it s of r an ge H ar dn es s H RC a t a d is ta nc e, i n m ill im et re s, f ro m q ue nc he d e nd o f t es t p ie ce Q ue nc hi ng te mp er at ur e N ame 1, 5 3 5 7 9 11 13 15 20 25 30 35 40 45 50 °C 20 Cr 3 + H m ax 48 46 41 34 31 29 27 25 22 – – – – – – 90 0 ± 5 m in 40 34 27 22 20 – – – – – – – – – – 20 Cr 4+H m ax 49 48 46 42 38 36 34 32 29 27 26 24 23 – – 90 0 ± 5 m in 41 38 31 26 23 21 – – – – – – – – – 20 M nC r4 –2+ H m ax 49 48 46 42 39 37 34 33 32 30 28 26 24 – – 90 0 ± 5 m in 41 38 31 28 24 21 – – – – – – – – – 17 M nC r5 +H m ax 47 46 44 41 39 37 35 33 31 30 29 28 27 – – 90 0 ± 5 m in 39 36 31 28 24 21 – – – – – – – – – 19 M nC r5 +H m ax 49 49 48 46 43 42 41 39 37 35 34 33 32 – – 90 0 ± 5 m in 41 39 36 33 30 28 26 25 23 21 – – – – – 15 Cr M o4 +H m ax 46 45 41 38 34 31 29 28 26 25 24 24 23 23 22 90 0 ± 5 m in 39 36 29 24 21 20 – – – – – – – – – 20 Cr M o4 +H m ax 48 48 47 44 41 39 37 35 33 31 30 30 29 29 28 90 0 ± 5 m in 40 39 35 31 28 25 24 23 20 20 – – – – – 20 M nC rM o4 –2+ H m ax 48 46 40 34 29 27 25 24 21 – – – – – – 90 0 ± 5 m in 41 37 27 22 – – – – – – – – – – – 20 M nN iC rM o3 –2 +H m ax 49 48 45 42 36 33 31 30 27 25 24 24 23 – – 90 0 ± 5 m in 41 37 31 25 22 20 – – – – – – – – – 20 Ni Cr M o7+ H m ax 48 47 45 42 39 36 34 32 29 26 25 24 24 24 24 90 0 ± 5 m in 40 38 34 30 27 25 23 22 20 – – – – – – 18 Cr Ni M o7 –6 +H m ax 48 48 48 48 47 47 46 46 44 43 42 41 41 – – 86 0 ± 5 m in 40 40 39 38 37 36 35 34 32 31 30 29 29 – –
Table 5 — (continued) ig na ti on Li m it s of r an ge H ar dn es s H RC a t a d is ta nc e, i n m ill im et re s, f ro m q ue nc he d e nd o f t es t p ie ce Q ue nc hi ng te mp er at ur e 1, 5 3 5 7 9 11 13 15 20 25 30 35 40 45 50 °C 4– 6+ H m ax 48 47 47 46 46 46 46 46 46 46 45 45 44 44 43 83 0 ± 5 m in 40 39 39 38 38 38 38 37 37 36 34 33 32 31 30 –5 +H m ax 48 47 47 46 46 46 46 46 46 46 45 45 44 44 43 83 0 ± 5 m in 40 39 39 38 38 38 38 37 37 36 34 33 32 31 30 m ax – – – – – – – – – – – – – – – – m in – – – – – – – – – – – – – – – a m ax – – – – – – – – – – – – – – – – m in – – – – – – – – – – – – – – – a m ax – – – – – – – – – – – – – – – – m in – – – – – – – – – – – – – – – H m ax 61 61 61 60 60 59 59 58 56 53 51 48 47 46 45 84 0 ± 5 m in 53 53 52 51 49 43 40 37 34 32 31 30 30 29 29 ir em en ts f or h ar de na bi lit y m ay b e a gr ee d u po n.
Table 6 — Hardness in the usual conditions of delivery
Steel designation Hardness in the delivery condition
Name HBW max HBW max HBW HBW max HBW max HBW
Steel designation Hardness in the delivery condition
Name HBW max HBW max HBW HBW max HBW max HBW
X75WCrV18–4-1 h – – 269 f – a For case-hardening steels, this condition is applied if cold forming operations are intended For through-hardening, stainless and high-temperature bearing steels, this condition is also used if the steel is processed by machining operations. b If this condition is needed, maximum hardness values and requirements concerning the structure are to be agreed upon at the time of enquiry and order. c The hardness of wire for needle bearings shall be up to 331 HBW The maximum Vickers hardness value (HV) must be agreed upon at the time of enquiry and order. d The hardness for cold-finished tubes shall be up to 321 HBW. e Under suitable conditions, this grade is shearable in the untreated condition. f Depending on the degree of cold working, the values may be up to about 50 HBW above those for condi- tion +AC Where necessary, exact requirements may be agreed upon at the time of enquiry and order. g Depending on the chemical composition of the cast, and on the dimensions condition +A might be nec- essary. h Shearability will, in general, only apply in condition +AC or in condition +A (for grade
13MoCrNi42–16–14 only). i The hardness for bright steel products with diameter < 13 mm must be < 320 HBW.
Table 7 — Test unit, number or sample products and test pieces and sampling and test methods for the different requirements
No Requirements Test unit a Number of Sampling b
Test method See sample prod- ucts test pieces sample product
2 Hardenability in the end- quench test d C 1/cast 1 ISO 642 ISO 642 e
4a Austenitic grain size d C 1/cast 1 ISO 643 ISO 643
4b Spheroidization of car- bides C, T, D f g g g ASTM A892 or
4d Microscopic non-metallic inclusions C k g g Annex A.5 Annex A.5
5 Surface decarburization i C, T, S, D g g ISO 3887 ISO 3887 a The tests are to be carried out for each cast, as indicated by “C” – each heat-treatment condition as indicated by
“T” – each surface condition as indicated by “S” – and each dimension, as indicated by “D”. b For all requirements, the general conditions for sampling according to ISO 377 apply. c The cast analysis shall be given by the manufacturer. d Applies only for case-hardening and induction-hardening bearing steels. e Quenching temperatures: see Table 5. f Products of small differences in thickness (about 1:1,5) can be considered as one test unit. g Shall be agreed upon at the time of enquiry and order. h Depending on the agreement at the time of enquiry and order, either the blue fracture test (see ISO 3763) or the etching test (see ISO 4969) or the step down test or the non-destructive test. i Applies only for through-hardening, stainless and high-temperature bearing steels. k The test unit may be agreed upon at the time of enquiry and order.