Suitable bolting materials for lower application temperatures must be determined by the manufacturer on the basis of the risk analysis carried out with regard to the types of failure determined (e.g. brittle fracture).
PED requirements
According to the ESRs of Annex I point 4.1 of the PED, materials must have properties that meet all reasonably foreseeable conditions of use, in particular sufficiently high ductility and toughness. In particular, the materials must be selected in such a way that brittle fracture does not occur.
According to Annex I, point 7.5, a steel is generally considered to be sufficiently ductile if its elongation value in the tensile test carried out in accordance with the standard procedure its elongation after rupture is no less than 14 % and its bending rupture energy measured on an ISO V test-piece is no less than 27 J, at a temperature not greater than 20 °C but not higher than the lowest scheduled operating temperature.
Requirements of EN 13445-2 for bolting material
All harmonised standards of materials have specified impact requirements, also EN 10269 “Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties“.
Table 1: Requirements for prevention of brittle fracture with reference thickness for nuts and bolts for TM ≥ -10 °C
| Standard | Type of material a) | Thickness limit | Impact test required for TM ≥ -10°C | Impact Test requirements | Lowest TM | Max. design temperature limit |
|---|---|---|---|---|---|---|
| EN 10269 (C35E) | 1.1181+N 1.1181+QT 1.1181+QT | d ≤ 60 mm d ≤ 60 mm 69 < d ≤ 150 | yes | min. 27 J min. 55 J min. 39 J | -10°C | 400 °C |
| EN 10269 (C45E) | 1.1191+N 1.1191+QT 1.1191+QT | d ≤ 60 mm d ≤ 60 mm 69 < d ≤ 150 | yes | min. 27 J min. 50 J min. 35 J | -10°C | 350°C |
| EN ISO 898-1 | 5.6 | M≤39 | M≥16 | TKV = RTb) / min. 40 J | -10°C | 300°C |
| 8.8 | M≤39 | M≥16 | TKV = RTb) / min. 52 J | -10°C | 300°C | |
| EN ISO 898-2 | 5 | M≤39 | None | – | -10°C | 300°C |
| 8 | M≤39 | None | – | -10°C | 300°C | |
| RT = Room Temp. TKV = Test Temp. TM = lowest minimum Metal Temp. |
EN ISO 898-1 and EN ISO 898-2 is suitable only for temperatures up to 50°C;
b) Testing in accordance with EN 10269; Additional testing is required to comply with TM = -20°C in accordance with EN ISO 898-1 point 9.14;
Note 1: If TM is lower than −10 °C, specified impact energy of minimum 40 J is required at TKV ≤ TM;
Table 2: Requirements for prevention of brittle fracture with reference thickness for nuts and bolts in acc. to EN ISO 3506
Standard | Type of material a) | Thickness limit | Impact test | lowest TM | max. design temperature limit |
|---|---|---|---|---|---|
| EN ISO 3506-1 (Bolts & studs) | A2-50 A3-50 | M ≤ 39 | None | -200°C | 400°C |
| A2-70 A3-70 | M ≤ 24 | None | -200°C | 400°C | |
| A4-50 A5-50 | M ≤ 39 | None | -60°C | 400°C | |
| A4-70 A5-70 | M ≤ 24 | None | -60°C; -200°C b) | 400°C | |
| EN ISO 3506-2 (Nuts) | A2-50 A3-50 A4-50 A5-50 | M ≤ 39 | None | -200°C | 400°C |
| A2-70 A3-70 A4-70 A5-70 | M ≤ 24 | None | -200°C | 400°C |
b) For studs or hot forged bolts with head in property;
Table 3: Bolting material EN 10269
| Material Name | Material No. | Thickness Limit | Impact test min. 40J | lowest TM | max. design temperature limit |
|---|---|---|---|---|---|
| X5CrNi18-10 | 1.4301+AT 1.4301+C700 | d ≤ 160 mm d ≤ 35 mm | 60 J 50 J | -196°C | 550°C |
| X4CrNi18-12 | 1.4303+AT 1.4303+C700 | d ≤ 160 mm d ≤ 35 mm | 60 J 50 J | -196°C | 550°C |
| X2CrNi18-9 | 1.4307+C700 | d ≤ 35 mm | 50 J | -196°C | 550°C |
| X5CrNiMo17-12-2 | 1.4401+C700 | d ≤ 35 mm | 50 J | -196°C | 550°C |
| X2CrNiMo17-12-2 | 1.4404+C700 | d ≤ 35 mm | 50 J | -196°C | 550°C |
| X6CrNiMoB17-12-2 | 1.4919+AT | d ≤ 160 mm | 60 J | -196°C | 600°C |
| X6CrNiTiB18-10 | 1.4941+AT | d ≤ 160 mm | 60 J | -196°C | 600°C |
| X6CrNi18-10 | 1.4948+AT | d ≤ 160 mm | 60 J | -196°C | 600°C |
| X2CrNiMoN17-13-3 3CrNiMoBN17-13-3 X6NiCrTiMoVB25-15-2 | 1.4429+AT 1.4910+AT 1.4980+AT+P | d ≤ 160 mm d ≤ 160 mm d ≤ 160 mm | 50 J 50 J 40 J | -273°C -273°C -196°C | 600°C 600°C 650°C |
| 20Mn5 | 1.1133+N | d ≤ 60 mm | 47 J | -20°C | 400°C |
| 20MnB4 | 1.5525+QT | d ≤ 16 mm | 40 J | -20°C | – |
| 25CrMo4 | 1.7218+QT | d ≤ 60 mm | 40 J | -60°C | 500°C |
| 1.7218+QT | 60 < d ≤ 100 mm | 40 J | -50°C | 500°C | |
| 30CrNiMo8 34CrNiMo6 42CrMo4 | 1.6580+QT 1.6582+QT 1.7225+QT | d ≤ 100 mm d ≤ 100 mm d ≤ 60 mm | 40 J 40 J 40 J | -40°C -40°C -40°C | 100°C 100°C 500°C |
| X12Ni5 | 1.5680+NT | d ≤ 40 mm | 40 J | -120°C | 300°C |
| 1.5680+NT | 40 < d ≤ 75 mm | 50 J | -90°C | 100°C | |
| X8Ni9 | 1.5662+N+NT 1.5662+QT | d ≤ 75 mm d ≤ 75 mm | 40 J 70 J | -196°C -196°C | 300°C |
– A specified impact energy of minimum 40 J is required at TKV = RT for TM ≥ -10°C;
– If TM is lower than -10°C, specified impact energy of minimum 40J is required at TKV ≤ TM;
– Bolting material with a design temperature below –160°C shall be impact tested at -196 °C;
