17-4 Project 70+

17-4 Project 70+ Stainless Steel is reported to have superior machinability characteristics versus standard 17-4. It is a martensitic stainless steel that is used in a wide range of applications due to its strong combination of high strength and excellent resistance to corrosion. Specifications include ASTM A564 and ASTM F899.

Common Applications

Due to the material’s high strength and machinability, 17-4 Project 70+ is used in a wide range of applications:

• Aerospace structural parts
• Surgical & dental instruments
• Firearms

Medical Application Details

Due to the material’s high strength and machineability with an ASTM F899 specification, the grade is used in a wide range of surgical instruments. However, in contrast to other grades, 17-4 Project 70+ is not an implantable metal. Instead, it is primarily used for various surgical instruments including but not limited to surgical scissors, ear pins, rollers and guides.

Material Characteristics 

17-4 Project 70+ has excellent mechanical properties that result in both strong corrosion resistance and improved machineability. The material’s corrosion resistance is comparable to both 304 and Custom 630.

As a vacuum remelted, precipitation-hardened grade, the material allows for faster machining times and improved feed rates. Project 70+ can be headed, rolled and formed by cold working in addition to resistance welded and shield-fusioned.

The grade meets both aerospace and medical requirements including ASTM F899 and ASTM A564.

Additional Information:

Martensitic Stainless Steel (17-4 PH Classification)

Stainless steels fall into four main categories: martensitic, austenitic, ferritic, and duplex. Martensitic stainless steels are defined by material that can be tempered and hardened by aging or heat treatment.

Martensitic material can be sub-divided into two categories:

1) High carbon material (above 0.4% carbon) used mainly for wear resistance (surgical instruments, molds, etc.)

2) Low carbon material (below 0.4% carbon) used mostly for their mechanical properties (shafts, valves, etc.)

Relative to other martensitic material, 17-4 has a low carbon content (<0.07%).