17-7PH Stainless steel

17-7PH Stainless steel bar, 17-7PH steel plate

17-7Ph is a type of Austenitic-Martensite precipitation hardened stainless steel developed base on 18-8CrN,that’s 631 stainless steel. After solid solution treatment, stainless steel 17-7ph will become unstable Austenite tissue, then cooling to precipitate carbide, and then Martensite transformation will be conducted. Most of the tissues will be transformed into low-carbon tempered Martensite with better toughness. The corrosion resistance of 17-7PH is better than that of ordinary Martensitic stainless steel.

17-7PH is characterized by high strength and hardness, excellent fatigue properties, good corrosion resistance and minimum distortion on heat treatment after heat treatment. The molding properties and elasticity of annealed 17-7PH are similar to 301. Under heat treatment conditions of TH1050 and RH950, the corrosion resistance of 631 is better than that of ordinary hardened stainless steels (such as 410, 420 and 431), but not as good as 304. After heat treatment, the corrosion resistance of CH900 is similar to 304 in most environments.

Available forms and specifications

UNS Specifications
S17700 AMS 5568 Welded Tubing

AMS 5528 Sheet, Strip and Plate

AMS 5529 Sheet, Strip Cold Rolled

AMS 5644 Bars and Forgings (Cap. ASTM A 564 Type 631)

AMS 5678 Wire

AMS 5824 Welding Wire

ASTM A 693, ASTM A 313, ASTM A 564, ASTM A 579 and ASTM A 705

ASME SA 564, SA 693 and SA 705

Chemical composition:

C Mn Si Cr Ni P S Al
≤0.09 ≤1.00 ≤1.00 16.0~18.0 6.5~7.75 ≤0.04 ≤0.03 0.75~1.5

Mechanical Properties:

Density,g/c㎡ 7.65 Kg/m³
Melting range,℃ 1404-1440°C
Tensile strength, min, Mpa 896 MPa
Yield strength, 0.2% offset, min, Mpa 276


Elongation, A5% 35
Hardness Rockwell C B85


  • Chemical processing equipment
  • Aerospace applications
  • Oil and petroleum refining equipment
  • Food processing equipment

LKALLOY is an industry leading manufacturer and supplier of 17-7Ph and other high-quality stainless steel alloys. We stock 17-7Ph stainless steel in the form of sheet, plate, bar,tubing and strip which are used for several applications such as springs, washers, blades, pressings, flexures, encapsulated bellows and etc.

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