17-4 Ph Condition A

17-4 Ph Condition A (AISI 630 Annealed) 
Precipitation Hardening Stainless Steel.


AISI 630 is commonly referred to as 17-4 and is a precipitation-hardening martensitic 
stainless steel. Its name derives from its chemical content which contains 17%
chromium and 4% nickel, which makes it superior in corrosion resistance to the regular
chromium-type martensitic stainless steels. An addition of copper is made to promote its
precipitation hardening capability. 

AISI 630 is magnetic in both the solution annealed and precipitation hardened condition.
AISI 630 is used for parts requiring corrosion resistance and high strength at room
temperature or at temperatures up to 600°F. It is suitable for machining in the solution-
annealed condition. After which, it can be age hardened to the specified mechanical
properties, without danger of cracking or distortion.


There are several heat treatments which are coded as H900, H925,
H1025, H1075, H1100 and H1150. The number represents the heat treatment temperature
employed. As this temperature increases, the developed strength declines but ductility


The corrosion resistance of AISI 630 is superior to that of
any standard martensitic hardenable stainless steels. In most applications and media, it is
equivalent to type 304 stainless steel.


Due to the high strength in all conditions, it has limited cold workability.
When fabrication requires cold forming prior to age hardening, the material
is normally supplied in over-aged condition or in H1150M.


AISI 630 should be heated uniformly to 2150°F–2200°F. If heating is
required, forging should be thoroughly soaked at temperature before rework. Immediately
after forging, the part should be returned to a heating furnace operating between 1900°F
and forging temperature to equalize temperature prior to cooling.
Non-uniformity in temperature of the section may promote cracking on cooling.


AISI 630 can be machined in the solution-treated condition and at
lower rates in the other conditions. Machining rates of AISI 630 are similar to type 304
stainless steel. In heat treated conditions, material should be machined moderately.


AISI 630 is readily welded by conventional heliarc method. Welding
procedures are essentially same as those used for other chromium-nickel-type stainless
steels. No preheating or post annealing is required as encountered with the martensitic
400 type stainless steels. The use of 630 or Type 308 electrodes is recommended for
welding, with the choice depending upon whether or not high strength is to be developed
after welding.


The Montrose Group are delighted to be exclusive agents for the sale of Cogne's AISI 630 Annealed material,
as a result of this partnership The Montrose Group will be stocking Cogne material in 17-4 Ph Condition A
from 1/2" DIA up to 12" DIA.

Material is available for next day delivery on straight lengths and one to two day delivery for cut pieces