Specifying stainless steel for spring applications
Introduction
European standards now cover both strip and wire products for springs. BS EN 10151:2002 applies to strip and replaces BS5770 part 4:1981, which is now withdrawn. BS EN ISO 6931-1:2020 applies to wire and replaces BS EN 10270-3:2001 which had previously replaced BS2056:1991, full details of the historical evolution of the standards can be found at the BSI website. Both standards use the European steel grade number system, most of which are also shown in BS EN 10088-1
BSEN 10151 stainless steel strip for springs
BS EN 10151 was published in 2002 and replaced BS5770 part 4, (1981), which is now withdrawn. It contains 10 grades, one ferritic, three martensitics, one precipitation hardening and five austenitic. With the exception of austenitic grade 1.4369, (X11CrNiMnN19-8-6), the grade compositions are covered by BS EN 10088-2. The composition of grade 1.4369 has been designed to keep the steel non-magnetic in all conditions. The BS EN 10151 has a more comprehensive scope than BS5770:4.
BS EN 10151 grade 1.4310 is the alternative to BS5770 grade 301S21, 1.4301, the alternative to 302S25 and 1.4401 the alternative to 316S16 in the austenitic types. Grades 1.4021 and 1.4028 are the BSEN 10151 alternatives to martensitic BS5770, 420S29 and 420S45 grades.
The other main difference between the standards is the way in which the ‘spring temper’ is specified. BS EN 10151 uses tensile strength ranges, rather than the Vickers hardness ‘conditions’ of BS5770:4. (TR230, TR280, TR330, TR380 etc depending on grade)
BS EN 10151 grades and delivery conditions
The compositions of all the grades are shown below.
Values are maxima, unless there is a range stated.
| Steel name |
Number |
C |
Si |
Mn |
P |
S |
N |
Cr |
Mo |
Ni |
Others |
| X6Cr17 |
1.4016 |
0.08 |
1.00 |
1.00 |
0.040 |
0.015 |
– |
16.0/18.0 |
– |
– |
– |
| X20Cr13 |
1.4021 |
0.16/0.25 |
1.00 |
1.50 |
0.040 |
0.015 |
– |
12.0/14.0 |
– |
– |
– |
| X30Cr13 |
1.4028 |
0.26/0.35 |
1.00 |
1.50 |
0.040 |
0.015 |
– |
12.0/14.0 |
– |
– |
– |
| X39Cr13 |
1.4031 |
0.36/0.42 |
1.00 |
1.00 |
0.040 |
0.015 |
– |
12.5/14.5 |
– |
– |
– |
| X7CrNiAl17-7 |
1.4568 |
0.09 |
0.70 |
1.00 |
0.040 |
0.015 |
– |
16.0/18.0 |
– |
6.5/7.8 |
Al:0.70/1.50 |
| X10CrNi18-8 |
1.4310 |
0.05/0.15 |
2.00 |
2.00 |
0.045 |
0.015 |
0.11 |
16.0/19.0 |
0.80 |
6.0/9.5 |
– |
| X5CrNi18-10 |
1.4301 |
0.07 |
1.00 |
2.00 |
0.045 |
0.015 |
0.11 |
17.5/19.5 |
– |
8.0/10.5 |
– |
| X5CrNiMo17-12-2 |
1.4401 |
0.07 |
1.00 |
2.00 |
0.045 |
0.015 |
0.11 |
16.5/18.5 |
2.0/2.50 |
10.0/13.0 |
– |
| X11CrNiMnN19-8-6 |
1.4369 |
0.07/0.15 |
0.50/1.00 |
5.0/7.5 |
0.030 |
0.015 |
0.20/0.30 |
17.5/19.5 |
– |
6.5/8.5 |
– |
| X12CrMnNiN17-7-5 |
1.4372 |
0.15 |
1.00 |
5.5/7.5 |
0.045 |
0.015 |
0.05/0.25 |
16.0/18.0 |
– |
3.5/5.5 |
– |
The specified tensile ranges and the ‘available’ tensile strength levels, by grade, are tabulated below.
| Steel name |
Number |
+C700 |
+C850 |
+C1000 |
+C1150 |
+C1300 |
+C1500 |
+C1700 |
+C1900 |
Hardness |
| X6Cr17 |
1.4016 |
X |
X |
NA |
NA |
NA |
NA |
NA |
NA |
200/300 |
| X20Cr13 |
1.4021 |
X |
X |
NA |
NA |
NA |
NA |
NA |
NA |
– |
| X30Cr13 |
1.4028 |
X |
X |
NA |
NA |
NA |
NA |
NA |
NA |
– |
| X39Cr13 |
1.4031 |
X |
X |
NA |
NA |
NA |
NA |
NA |
NA |
– |
| X7CrNiAl17-7 |
1.4568 |
NA |
NA |
X |
X |
X |
X |
X |
NA |
– |
| X10CrNi18-8 |
1.4310 |
NA |
X |
X |
X |
X |
X |
X |
X |
250/600 |
| X5CrNi18-10 |
1.4301 |
X |
X |
X |
X |
X |
NA |
NA |
NA |
220/450 |
| X5CrNiMo17-12-2 |
1.4401 |
X |
X |
X |
X |
X |
NA |
NA |
NA |
220/400 |
| X11CrNiMnN19-8-6 |
1.4369 |
NA |
X |
X |
X |
X |
X |
NA |
NA |
300/475 |
| X12CrMnNiN17-7-5 |
1.4372 |
NA |
X |
X |
X |
X |
X |
NA |
NA |
250/500 |
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. Steels 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 Designation |
Approximate Equivalent UTS Range (MPa) |
Nearest Equivalent Condition in EN 10151 |
| TR 500 |
> 1550 |
+C1500 |
| TR 380 |
> 1230 |
+C1300 |
| TR 330 |
1050/1230 |
+C1000/+C1150 |
| TR 280 |
910/1050 |
+C850/+C1000 |
| TR 230 |
750/910 |
+C700/+C850 |
BS EN ISO 6931-1:2020 Stainless steels for springs: Part 1 : Wire
BS EN ISO 6931-1: 2020 has replaced BS EN 10270-3 which was published in 2001, which in turn had replaced BS 2056 (1991), both of which are now withdrawn. It contains 8 grades, six austenitic, one duplex and one precipitation hardening. (The grade compositions are also covered by BS EN 10088-3)
The BS EN ISO 6931-1:2020 has more grades than BS EN 10270-3 :2001, but unlike the original standard BS 2056:1991, it still does not include the hardenable martensitic 420S45. There still is 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. BS EN ISO 6931-1:2020 grade numbers 4310…. and 4325… are the alternatives to BS 2056, 302S26 and 4401… the alternative to 316S33 and 316S42. Grade number 4568… in BS EN ISO 6931-1:2020 is a 17-7 PH precipitation hardening stainless steel. The original standards should be consulted for grade comparisons.
BS EN ISO 6931-1:2020 grades and delivery conditions
The compositions of all the grades are shown below.
Values are maxima, unless there is a range stated.
| Name |
Number |
C |
Si |
Mn |
P |
S |
Cr |
Mo |
Ni |
Others |
| Austenitic Steels |
| X10CrNi18-8 |
4310-301-00-I |
0.05/0.15 |
2.00 |
2.00 |
0.045 |
0.015 |
16.0/19.0 |
0.80 |
6.0/9.50 |
N:0.10 |
| X9CrNi18-9 |
4325-302-00-E |
0.030/0.15 |
1.00 |
2.00 |
0.045 |
0.030 |
17.0/19.0 |
– |
8.0/10.0 |
N:0.10 |
| X5CrNiN19-9 |
4315-304-51-I |
0.08 |
1.00 |
2.50 |
0.045 |
0.030 |
18.0/20.0 |
– |
7.0/10.5 |
N:0.10/0.30, Nb:0.15 |
| X5CrNi18-10 |
4301-304-00-I |
0.07 |
1.00 |
2.00 |
0.045 |
0.015 |
17.5/19.5 |
– |
8.0/10.5 |
N:0.10 |
| X5CrNiMo17-12-2 |
4401-316-00-I |
0.07 |
1.00 |
2.00 |
0.045 |
0.015 |
16.5/18.5 |
2.00/3.0 |
10.0/13.0 |
N:0.10 |
| X1NiCrMoCu25-20-5 |
4539-089-04-I |
0.020 |
0.75 |
2.00 |
0.035 |
0.015 |
19.0/22.0 |
4.0-5.0 |
23.5/26.0 |
N:0.15, Cu: 1.20/2.00 |
| Austenitic-ferritic (duplex) steel |
| X2CrNiMoN22-5-3 |
4462-318-03-I |
0.030 |
1.00 |
2.00 |
0.035 |
0.015 |
21.0/23.0 |
2.50/3.50 |
4.5/6.5 |
N:0.10/0.22 |
| Precipitation hardening steel steel |
| X7CrNiAl17-7 |
4568-177-00-I |
0.09 |
0.70 |
1.00 |
0.040 |
0.015 |
16.0/18.0 |
– |
7.0/8.5 |
Al:0.70/1.50 |
The specified minimum tensile strength levels, by grade, in the drawn or heat treated, (4568… only), conditions are tabulated below.
| Steel number |
4310-301-00-I |
4310-301-00-I |
4325-302-00-E, 4315-304-51-I |
4301-304-00-I |
4301-304-00-I |
4401-316-00-I |
4539-089-04-I |
4462-318-03-I |
4462-318-03-I |
4568-177-00-I |
| Nominal diameter |
Drawn Normal |
Drawn High |
Drawn |
Drawn Normal |
Drawn High |
Drawn |
Drawn |
Drawn Normal |
Drawn High |
Heat Treated |
| Below 0.20 |
2200 |
2350 |
2150 |
2000 |
2150 |
1725 |
1600 |
2150 |
2370 |
1975 |
| 0.20-0.30 |
2150 |
2300 |
2050 |
1975 |
2050 |
1700 |
1550 |
2100 |
2370 |
1950 |
| 0.30-0.40 |
2100 |
2250 |
2050 |
1925 |
2050 |
1675 |
1550 |
2000 |
2370 |
1925 |
| 0.40-0.50 |
2050 |
2200 |
1950 |
1900 |
1950 |
1650 |
1500 |
2000 |
2370 |
1900 |
| 0.50-0.65 |
2000 |
2150 |
1900 |
1850 |
1950 |
1625 |
1450 |
1900 |
2370 |
1850 |
| 0.65-0.80 |
1950 |
2100 |
1850 |
1800 |
1850 |
1600 |
1450 |
1900 |
2230 |
1825 |
| 0.80-1.00 |
1900 |
2050 |
1850 |
1775 |
1850 |
1575 |
1400 |
1800 |
2140 |
1800 |
| 1.00-1.25 |
1850 |
2000 |
1750 |
1725 |
1750 |
1550 |
1350 |
1800 |
2090 |
1750 |
| 1.25-1.50 |
1800 |
1950 |
1700 |
1675 |
1750 |
1500 |
1350 |
1700 |
2090 |
1700 |
| 1.50-1.75 |
1750 |
1900 |
1650 |
1625 |
1650 |
1450 |
1300 |
1700 |
2000 |
1650 |
| 1.75-2.00 |
1700 |
1850 |
1650 |
1575 |
1650 |
1400 |
1300 |
1700 |
2000 |
1600 |
| 2.00-2.50 |
1650 |
1750 |
1550 |
1525 |
1550 |
1350 |
1300 |
1550 |
1900 |
1550 |
| 2.50-3.00 |
1600 |
1700 |
1450 |
1475 |
1550 |
1300 |
1300 |
1550 |
1860 |
1500 |
| 3.00-3.50 |
1550 |
1650 |
1450 |
1425 |
1450 |
1250 |
1300 |
1550 |
1850 |
1450 |
| 3.50-4.25 |
1500 |
1600 |
1450 |
1400 |
1450 |
1225 |
1250 |
1450 |
1750 |
1400 |
| 4.25-5.00 |
1450 |
1550 |
1350 |
1350 |
1350 |
1200 |
1250 |
1450 |
1700 |
1350 |
| 5.00-6.00 |
1400 |
1500 |
1350 |
1300 |
1150 |
1300 |
1250 |
1350 |
– |
1300 |
| 6.00-7.00 |
1350 |
1450 |
1270 |
1250 |
1300 |
1125 |
1200 |
1350 |
– |
1250 |
| 7.00-8.50 |
1300 |
1400 |
1130 |
1200 |
1300 |
1075 |
1150 |
– |
– |
1250 |
| 8.50-10.0 |
1250 |
1350 |
980 |
1175 |
1250 |
1050 |
– |
– |
– |
1250 |
Note for each diameter range, the properties quoted apply to the minimum diameter, but not to the maximum diameter.
← Back to previous
↑ Top
