ISO/TR 15608 Group 9.2 such as 12Ni14 steel :
Nickel alloy steels with 3,0 < Ni ≤ 8,0 %
Nickel alloy steels such as 12Ni14 steel for Cryogenic and Low-Temperature Service
Low-temperature steels generally refer to steels applied below 0℃. The addition of Ni and other alloying elements can reduce interstitial impurities, refine grain, control the size, shape and distribution of the second phase, etc., so as to reduce the Ductile – Brittle transition temperature of ferrite steel. Alloying elements in low temperature steel mainly affect the low temperature toughness of steel. The low-temperature toughness of steel increased by Nickel is 5 times as much as that of manganese, and the brittle transition temperature decreased by about 10℃ for every 1% increase in nickel content, which is mainly due to the fact that nickel was not reacted with carbon and all dissolved into the solid solution to strengthen it.
Applications for such steel plates ISO/TR 15608 material group 5.2 such as 2Ni14 steel
This material group retain adequate Charpy V-notch toughness, and thus high resistance to brittle fracture, even in the temperature range down to -185° C. This makes them the perfect choice for gas-liquefaction plants, for example, and for the transportation and storage of liquefied gases, such as LNG and LPG.
Welding of low temperature steels
The characteristic properties of welding consumables for welding Low-Temperature steels is their deformation capacity at low temperatures, which is usually tested using the notched bar impact bending test. The value of the impact energy is used to draw conclusions about the tendency to brittle fracture and the suitability for use up to a certain temperature. When welding at low temperature steels, attention must be paid to controlled heat input in order to keep the heat-affected zone as narrow as possible and still avoid hardening peaks.
Filler metals with higher nickel contents tend to increase hot cracking. The 5% nickel steel can be welded with austenitic filler metals, but the use of nickel-based types should be preferred if this base material is present. Heat treatment of the welded joint must then be omitted in consideration of the austenitic weld metal (embrittlement, carbon diffusion).
EN 13445: Cryogenic and low-temperature steels
Typical material in group 9.2
| Name/Grade | Number | Standard | Product | Remarks/Trade Mark |
|---|---|---|---|---|
| 12Ni14 12Ni14 12Ni14+QT 12Ni14 12Ni14+QT 12Ni14 D 3 3 WPL3 | 1.5637 1.5637 1.5637 1.5637 1.5637 1.5637 K31718 K31918 K31918 K31918 | EN 10028-4 EN 10216-4 EN 10216-4 EN 10222-3 EN 10222-3 EM 10253-2 ASTM A-203 ASTM A-333 ASTM A-334 ASTM A-429 | Plate Seamless tube Seamless tube Forgings Forgings Fittings Plate Smls. & welded pipe Welded tube Fittings | EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| E | K32018 | ASTM A-203 | Plate | CryElso® 203 ASME BPVC |
| LF3 | K32025 | ASTM A-350 | Forging | ASME BPVC |
| III III | K32026 – | ASTM A-765 ASTM A-553 | Forging Plate | ASME BPVC ASME BPVC |
| F | – | ASTM A-203 | Plate | ASME BPVC |
| G9Ni14 | 1.5638 | EN 10213 | Casting | EN 13445-2 & EN 13480-2 |
| X12Ni5 X12Ni5 X12Ni5+QT X12Ni5 | 1.5680 1.5680 1.4580 1.5680 | EN 10028-4 EN 10216-4 EN 10216-4 EN 10222-3 | Plate Seamless tube Seamless tube Forgings | CryElso® 5 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 |
| G17NiCrMo13-6 LC2–1 | 1.6781 J42215 | EN 10213 ASTM A-213 | Casting Casting | EN 13445-2 & EN 13480-2 ASME BPVC |