Stainless Steel for Spring Application | Heat Treatment of Stainless Steel for Spring Application

European standard now cover both stainless steel strip and wire for springs. EN 10151:2002 applies to strip and replaces BS5770 part 4:1981, which is now withdrawn. EN 10272-3:2001 applies to wire and replaces BS2056:1981. Both standards use the European steel grade number system, most of which are also shown in EN 10088-1

EN 10151 stainless steel strip for springs

EN 10151 was published in 2002 and replaced BS5770 part 4 (1981), which is now withdrawn. It contains 10 grades, one ferritic, three martensitic one precipitation hardening and five austenitic. With the exception of austenitic grade 1.4369 (X11CrNiMnN19-8-6), the grade compositions are covered by EN 10088-2. The composition of grade 1.4369 has been designed to keep the steel non magnetic in all conditions. The EN 10151 has a more comprehensive scope than BS5770:4.

EN 10151 grade 1.4310 is the alternative to BS5770 grade 301S21, 1.4301 the alternative to 304S25 and 1.4401 the alternative to 316S16 in the austenitic types. Grades 1.4021 and 1.4028 are the EN 10151 alternatives to martensitic BS5770, 420S29 and 420S45 grades.

The other main difference between the standard is the way in which the 'spring temper' is specified. EN 10151 uses tensile strength ranges, rather than Vickers hardness 'condition' of BS5770:4. (TR230, TR280, TR330, TR380 etc depending on grade)

 

EN 10151 grades and delivery conditions

The chemical composition of all the grades are shown below. Values are maxima, unless there is a range stated.

Steel nameNumberCSiMnPSNCrMoNiOthers
X6Cr171.40160.081.001.000.0400.015-16.0/18.0---
X20Cr131.40210.16
/0.25
1.001.500.0400.015-12.0/14.0---
X30Cr131.40280.26
/0.35
1.001.500.0400.015-12.0/14.0---
X39Cr131.40310.36
/0.42
1.001.000.0400.015-12.5/14.5---
X7CrNiAl17-71.45680.090.701.000.0400.015-16.0/18.0-6.5
/7.8
Al:
0.70
/1.50
X10CrNi18-81.43100.05
/0.15
2.002.000.0450.0150.1116.0/19.00.806.0
/9.5
-
X5CrNi18-101.43010.071.002.000.0450.0150.1117.5/19.5-8.0
/10.5
-
X5CrNiMo17-12-21.44010.071.002.000.0450.0150.1116.5/18.52.0
/2.50
10.0
/13.0
-
X11CrNiMnN19-8-61.43690.07
/0.15
0.50
/1.00
5.0/7.50.0300.0150.20
/0.30
17.5/19.5-6.5
/8.5
-
X12CrMnNiN17-7-51.43720.151.005.5/7.50.0450.0150.05
/0.25
16.0/18.0-3.5
/5.5
-

The specified tensile ranges and the 'available' tensile strength levels, by grade, are tabulated below.

Steel nameNumber+C700+C850+C
1000
+C
1150
+C
1300
+C
1500
+C
1700
+C
1900
Hardness
X6Cr171.4016XXNANANANANANA200
/300
X20Cr131.4021XXNANANANANANA-
X30Cr131.4028XXNANANANANANA-
X39Cr131.4031XXNANANANANANA-
X7CrNiAl17-71.4568NANAXXXXXNA-
X10CrNi18-81.4310NAXXXXXXX250
/600
X5CrNi18-101.4301XXXXXNANANA220
/450
X5CrNiMo17-12-21.4401XXXXXNANANA220
/400
X11CrNiMnN19-8-61.4369NAXXXXXNANA300
/475
X12CrMnNiN17-7-51.4372NAXXXXXNANA250
/500

Available tensile strength levels in MPa (N/mm2) are:-

+C700 = 700/850: +C850 = 850/1000: +C1000 = 1000/1150: +C1150 = 1150/1300; +C1300 = 1300/1500: +C1500 = 1500/1700: +C1700 = 1700/1900: +C1900 = 1900/2200

NOTES
Martensitic grades 1.4021, 1.4028 and 1.4031 should also be available in the annealed condition.

Precipitation hardening grade 1.4568 should also be available in the solution annealed condition.

Total hardness Vickers ranges apply to ferritic and austenitic types only. Steel can be supplied to any HV aim value within the range.

The table below shows approximate equivalents of the TR designations in BS 5770

BS 5770 DesignationApproximate Equivalent UTS Range (MPa)Nearest Equivalent Condition in EN 10151
TR 500> 1550+C1500
TR 380> 1230+C1300
TR 3301050/1230+C1000/+C1150
TR 280910/1050+C850/+C1000
TR 230750/910+C700/+C850

EN 10270-3 stainless steel wire for springs

EN 10270-3 was published in 2001 and replaced BS2056 (1991), which is now withdrawn. It contains only 3 grades, two austenitic and one precipitation hardening. (The grade compositions are also covered by EN 10088-3)

The EN 10270-3 has fewer grades than BS2056, which included the hardenable martensitic 420S45 and the highly alloyed austenitic 904S14 grades. There is also no austenitic with the enhanced nickel range of the 305S11 (11.0/13.0% Ni), which was for applications where low magnetic permeability in the cold drawn condition was required. EN 10270-3 grade 1.4310 is the alternative to BS2056 302S26 and 1.4401 the alternative to 316S33 and 316S42. Grade 1.4568 in EN 10270-3 is similar to the 301S81 of BS2056. These are NOT compositional equivalents. Annex B of BSEN 10270-3 shows a cross-reference table to former French, German and Swedish steel grades. The original standards should be consulted for grade comparisons.

EN 10270-3 grades and delivery conditions

The compositions of all the grades are shown below. Values are maxima, unless there is a range stated.

NameNumberCSiMnPSCrMoNiOther
X10CrNi18-81.43100.05/0.152.002.000.0450.01516.00/19.000.806.00/9.50N:
0.11
X5CrNiMo17-12-21.44010.071.002.000.0450.01516.50/18.502.00/2.5010.00/13.00N:
0.11
X7CrNiAl17-71.45680.090.701.000.0400.01516.00/18.00-6.50/7.80Al:
0.70
/1.50

The specified minimum tensile strength levels, by grade, in the drawn or heat treated (1.4568 only) conditions are tabulated below.

Steel number1.43101.43101.44011.45681.4568
Nominal diameterDrawn NormalDrawn HighDrawnDrawnHeat Treated
Below 0.2022002350172519752275
0.20-0.3021502300170019502250
0.30-0.4021002250167519252225
0.40-0.5020502200165019002200
0.50-0.6520002150162518502150
0.65-0.8019502100160018252125
0.80-1.0019002050157518002100
1.00-1.2518502000155017502050
1.25-1.5018001950150017002000
1.50-1.7517501900145016501950
1.75-2.0017001850140016001900
2.00-2.5016501750135015501850
2.50-3.0016001700130015001800
3.00-3.5015501650125014501750
3.50-4.2515001600122514001700
4.25-5.0014501550120013501650
5.00-6.0014001500115013001550
6.00-7.0013501450112512501500
7.00-8.5013001400107512501500
8.50-10.012501350105012501500

Note diameter ranges include the minimum figure, but exclude the maximum figure.

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