High-performance alloy material for industrial engineering and critical application conditions.
Scope of supply of Aviation Group:
Non-standard forgings, round rods, steel plates, rings, seamless pipes
1. Introduction to SUS631 Materials
SUS631 is an austenite-martensite precipitation hardened stainless steel developed based on 18-8CrNi, also known as controlled phase change stainless steel.
SUS631 is also a precipitation hardened stainless steel, with high strength and high hardness, fatigue resistance, good corrosion resistance and die forging performance, and minimal deformation under high temperature environment. This steel has excellent comprehensive performance and is especially suitable for aerospace industry. This special alloy is also applicable to other fields requiring high strength and corrosion resistance. It maintains stable spring performance up to 316°C. SUS631 is used in aerospace, chemical, petrochemical, papermaking and metal processing industries.
2. Chemical Ingredients
| alloy | C | Mn | Si | P | S | Cr | Ni | Al |
| SUS631 | – | – | – | – | – | 16.0 | 6.50 | 0.75 |
| 0.09 | 1.0 | 1.0 | 0.040 | 0.030 | 18.0 | 7.75 | 1.50 |
3. Physical properties
| density | 7.65g/cm³ |
| Melting point | 1415-1450℃ |
Mechanical properties of SUS631 alloy at room temperature
| Condition | Tensile strength Rm N/mm2 | Yield strength RP0.2 N/mm2 | Elongation A5 % | Brinell hardness HB |
| Solid melting 1000~1100℃ Quick cooling | ≤1030 | ≤380 | ≥20 | ≤229 |
| 565℃ aging | ≥1140 | ≥960 | ≥5 | ≥363 |
| 510℃ aging | ≥1230 | ≥1030 | ≥4 | ≥388 |
4. Material properties
SUS631 is a precipitation hardening stainless steel featuring high strength, high hardness, fatigue resistance, outstanding corrosion resistance and good die forging performance. After solid solution treatment, it presents unstable austenite structure with excellent plasticity, toughness and machinability. After phase adjustment, the precipitation of carbide phases inside austenite changes. Through martensite transformation treatment, most tissues transform into low-carbon tempered martensite with good toughness. This state is the service state of the steel, which possesses excellent medium-temperature mechanical properties. Its corrosion resistance outperforms ordinary martensitic stainless steel.
5. Application areas
Used in aerospace, chemical, petrochemical, papermaking and metal processing industries.
