631

HuaNickel 631 is an austenitic-martensitic precipitation hardened stainless steel developed on the basis of 18-8CrNi. It is also known as controlled phase change stainless steel.After solution treatment, it is an unstable austenite structure, with good plasticity and processability, after adjustment, the carbide phenology composition of austenite precipitation changes, and then after martensite transformation treatment, most of the structure is transformed into low-carbon tempered martensite with good toughness, which is the use state of steel and has good mechanical properties at medium temperature. The corrosion resistance is better than that of martensitic stainless steel.

631Chemical composition：

	Cr	Ni	AI	C	Si	Mn	P
Min	16	6.5	0.75	≤
Max	18	7.5	1.5	0.09	1	1	0.035

631Physical properties：

Density

7.8 g/cm³

631Mechanical properties：

Specification	State	σЬ MPa	σp0.2 MPa	δ5 (%)
		≥
–	Solid solution	≤1030	≤380	20
δ≤3.0	560℃aging(TH1050)	1140	960	3
δ >3.0				5
δ≤3.0	510℃aging（RH950）	1230	1030	–
δ >3.0				4

631Alloy properties：

It has good plasticity and processability

It has good mechanical properties at medium temperature

The corrosion resistance is better than that of martensitic stainless steel

631Uses of alloys：

Engine thrust reverser components

Valve diaphragm

stainless elastic elements, etc.,

Containers, conduits, springs, valve diaphragms, ship shafts

Compressor discs

631Process performance：

Heat treatment: 1050°C, water-cooled or air-cooled +760°C, 90min, air-cooled to no higher than 15°C+565°C, 90min, air-cooled

Processability:

Hot processing: the maximum heating temperature is 1150 °C, the open forging (rolling) temperature is about 1100 °C, the termination temperature should not be less than 950 °C, and the air cooling after forging and rolling.

Cold work: The tendency of cold work hardening is large, and it is advisable to adopt the method of less pass and large pressure and multiple intermediate solution treatment in cold rolling, cold drawing or stamping. Cold-worked finished products should be solved in a protective atmosphere.