Grade ss 630 type steel plates have good corrosion resistance in many environments. They exhibit improved resistance against stress corrosion cracking, if aged at 550°C or more. However, grade 630 steels are less resistant to solution treated Condition A, and hence these steels, even with considerable hardness, should not be used in this condition.

Heat Resistance

Grade ss 630 type steel plate have good resistance to oxidation. However, long-time exposure of grade 630 to temperatures of 370 to 480°C should be avoided, to prevent loss of toughness at ambient temperature. These grades should not be used at temperatures above age-hardening temperature, to avoid reduction of hardness and mechanical properties of the metal.

Cond.	Hardening	Typical Hardness Rockwell C	Tensile Strength (MPa)
Temp (°C)	Time (h)
A	Ann	-	36	1100
H900	482	1	44	-
H925	496	4	42	1170-1320
H1025	552	4	38	1070-1220
H1075	580	4	36	1000-1150
H1100	593	4	35	970-1120
H1150	621	4	33	930-1080

Welding

Grade 630 stainless steels can be welded using all conventional methods, and they do not require pre-heating. Care should be taken in designing and welding of high strength steels to prevent weldment stresses.

Machining

Grade 630 stainless steels can be machined in their solution-treated condition. They have machining rates similar to that of grade 304 steels.

Applications

Some of the major applications of grade 630 stainless steels include: