×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

shock tool steel
2

shock tool steel

shock tool steel

(OP)
Building hydraulic ironworker, been advised best material for shear blade would be A7
shock tool steel, hardened right through then tempered. If this is correct, what procedures/processes for hardening and tempering (low tech) would you advise we use?

RE: shock tool steel

2
The advice to use A7 tool steel (UNS T30107) was a good one.  Technically, it is an air-hardening, medium-alloy, cold-work steel, not a shock-resisting steel (these alloys begin with an S, like S7 [UNS T41907]).  A7 can be hardened to very high levels, which imparts excellent resistance to abrasion.

Air-hardening refers to the fact that this steel alloy does not need to be quenched in oil or water after hardening (austenitizing)-- air cooling represents a "quench" of sufficient rapidity to develop a fully martensitic microstructure.  This leads to excellent resistance to cracking and distortion.  Note that cracking means cracking due to heat treating, not fracture resistance, which is quite low, due to the high carbon content and hardness.

As for the procedure for heat treating, the key features are hardening and tempering for this alloy.  The part should be heated VERY SLOWLY from an initial preheat temperature of 815 C (1500 F) to the hardening temperature of 955-908 C (1750-1800).  Preheating can be eliminated, but cracking may occur if the rate of heating is too high.  The part should remain at the hardening temperature for 30-60 minutes, depending on mass, thickness, etc.

Tempering should be done at 150-540 C (300-1000 F), depending on the desired hardness, for at least 1 hour.  Multiple tempers of 2 hours or more may be used to develop optimum strength and toughness.  The time to reach the tempering temperature depends on the section size and thickness.  An average flat shape will take about 3 minutes/mm (75 minutes/inch) to reach 150 C.  Anything greater than 480 C will take 1.6 min/mm (40 min/inch).  These numbers are for a hot air oven without circulation.  Circulating air ovens or oil baths would be more like 1.2 min/mm for either temperature.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close