631 S17700 17-7PH 1.4568 Precipitation Hardening Stainless Steel
631 S17700 17-7PH 1.4568 Precipitation Hardening Stainless Steel
631 1.4568 Stainless steel from the group of age-hardened PH with the highest content of Chromium – 17% and Nickel – 7% in relation to PH of grades 15-5 and 17-4. It has excellent strength properties, high hardness and elasticity, good corrosion resistance and resistance to high temperatures and deformation.
Application
The material is used on valve parts, tanks, springs, spring washers, food knives, diaphragms, low and high temperature parts, heat exchangers, special fittings and installations, machine constructions and components. Steel is intended for the aerospace, petroleum, chemical and petrochemical industries, energy, food and cryogenic industry in the form of strips, wires, sheets and bars.
Equivalent grades of steel X7CrNiAl17-7 (1.4568)
| EU EN | USA – | France AFNOR | England BS | Sweden SS | Russia GOST | Inter ISO |
| X7CrNiAl17-7 | 631 | Z9CNA17-07 | 301S81 | 2388 | 09KH17N7YU | X7CrNiAl17-7 |
Chemical Component
| C: | Mn: | Si: | P: | S: | Cr: | Ni: | Al: |
| <0.09 | <1.0 | <0.5 | <0.025 | <0.025 | 16.00 – 17.25 | 6.50 – 7.75 | 0.75 – 1.25 |
Smelting Option
1 EAF: Electric Arc Furnace
2 EAF+LF+VD: Refined-smelting and vacuum degassing
3 EAF+ESR: Electro Slag Remelting
4 EAF+PESR: protective atmosphere Electro Slag Remelting
5 VIM+PESR: Vacuum induction melting
Forming Option
1 Hot rolling process
2 Hot Forging: Electro-hydraulic; High-speed-hydraulic; Oil-hydraulic; Precision-forging
Heat-treatment Option
1 +A: Annealed (full/soft/spheroidizing)
2 +N: Normalized
3 +NT: Normalized and tempered
4 +QT: Quenched and tempered (water/oil)
5 +AT: Solution annealed
6 +P: Precipitation hardened
Suface Option
1 Black Surface
2 Grounded: Bright but rough ; Not precision
3 Machining for plate: Bright and precision; Little turning scar
4 Peeled/Turned: Bright and precision; Little turning scar
5 Polished: Very Bright and precision size; Not turning scar
Other Services
1 Cutting: Small pieces
2 CNC Machine: Produce as your drawing
3 Package: Bare/Nylon/Canvas/Wooden
4 Payment:T/T, L/C, O/A(request credit)
5 Transport:FOB/CFR/CIF/DDU/DDP (train/ship/Air)
Mechanical Property
| Proof strength Rp0.2 (MPa) | Tensile strength Rm (MPa) | Impact energy KV (J) | Elongation at fracture A (%) | Reduction in cross section on fracture Z (%) | As-Heat-Treated Condition | Brinell hardness (HBW) |
| 685 (≥) | 438 (≥) | 41 | 23 | 44 | Solution and Aging, Annealing, Ausaging, Q+T,etc | 242 |
Heat treatment
Condition A – Saturation at 1065O C
Condition TH1050 – Saturation at 1400 F (760 C) for 1.5 hours, cooled for 1 hour to 55 F (15 C) for 0.5 hours, then aged at 1050 F (566 C) for 1.5 hours
Condition RH950 – Saturation at 1750 F (954 C) for 10 minutes with air cooling, product cooling to -100F (-73 C) for about 1.5 hours, aging at 950 F (510 C) for 1 hour
Condition C – Condition after cold rolling
Condition CH900 – Cold rolled condition after ageing at 900 F (482 C) for 1.0 hours with air cooling
Welding
Common arc and resistance methods can be used with stainless steel grade 17-7 PH. It is recommended that during fusion welding inert gas shielding should be performed to reduce the oxidation of aluminum during the process.
Aging
Stainless steel grade 17-7 PH is solution annealed at 1177°C (2150°F) for 4 h and air cooled. Same step is performed at 1079°C (1975°F) for 4h and air cooled, then at 843°C (1550°F) for 24h and air cooled, and at 760°C (1400°F) for 16h and air cooled. This completed the precipitation hardening process. For excellent results and performance, the material should be clean and free from scale and impurities.
Machinability
Machinability of stainless steel grade 17-7 PH is rated at 75 % of B1112. On machining, this alloy displays long gummy chips and requires chip breakers. It is recommended that slow speeds and constant feeds while machining will provide excellent results.
