Canadian Flag Canadian Centre for Occupational Health and Safety Centre canadien d'hygiène et de sécurité au travail Government of Canada Wordmark
CCOHS: Canadian Centre for Occupational Health and Safety
Français Contact Us Help
        
Canada Site
Web Info Service Products & Services OSH Answers Education & Training
Canada's national Occupational Health & Safety Resource
Home About Us E-News Bringing Health to Work Events Resources
OSH Answers Lists
What's New!
Subject Categories
Metalworking Machines
Drill Presses
General
Heat-treating
Lathes
Metal Saws (Cold)
Metal Saws (Hot)
Milling Machines
Planers
Surface Grinders
Related Products and Services

Courses:
Electrical Hazards
Lockout
More Information
About OSH Answers
Feedback
Disclaimer
Inquiries Service

The Inquiries Service at CCOHS answers questions on the health or safety concerns people have about the work they do.

About the Inquiries Service
Ask a Question

Heat-treating

What should you know before participating in heat-treating operations?
What are some safety precautions to follow during a heat-treating operation?
What are some things you should avoid doing?


What should you know before participating in heat-treating operations?

Heat-treating operations require a quench as an integral part of the process. Liquid quenches normally involve the use of mineral oils, water-based solutions or molten salt. Less severe quenches use circulated gases or forced air, or involve cooling in still air. Refer to Metalworking Machines - General for basic safety tips.

Quenching operations pose various health hazards to workers. These include working in high temperatures and the risk of fire or explosion.

Consider the properties of the quenchants plus the design, construction, location, control, monitoring and maintenance of the furnace itself to minimize these risks.

Quenching operations are often followed by a degreasing with chlorinated solvents or water-soluble compounds.

Only operate heat-treating equipment when properly trained.

What are some safety precautions to follow during a heat-treating operation?

  • Wear a face shield, safety glasses, gloves and heat-resistant protective clothing when working with hot metal. Quench oils may be very hot (above 100C) and oil temperature increases during quenching. Splashes or skin contact cause burns. Avoid skin contact with oils by using gloves and protective clothing.
  • Check that all safety devices, such as automatic shut-off valves, air switches, and exhaust fans are working properly before lighting the furnace.
  • Ensure that quenching areas have enough ventilation to keep oil mists at recommended levels.
  • Follow the manufacturer's instructions when lighting the furnace.
  • Stand to one side when lighting a gas- or oil-fired furnace.
  • Ensure that water does not contaminate the quenching oil. Any moisture which comes in contact with the oil can cause an explosion.
  • Use the proper tongs for the job and make sure the tongs are dry before removing any work from a liquid carburizing pot.
  • Ensure that a suitable bacterial inhibitor or fungicide has been added to the quenching liquid.
  • Cover quench tanks when not in use.
  • Clean up oil spills and leaks immediately using a nonflammable absorbant.
  • Keep work areas, jigs, baskets and tools free from oil contamination where possible.
  • Wash hands thoroughly after work, at breaks (particularly meal times), before starting other tasks, or before using the toilet.
  • Obtain first aid for all cuts and abrasions. Protect them from contamination by using suitable dressings.
  • Report to your supervisor and obtain medical attention when suffering from, or suspecting, skin trouble.
What are some things you should avoid doing?

  • Do not inhale the fumes from a molten carburizing salt bath. During the carburizing process, carbon monoxide is generated. Ensure that this area is well ventilated. These molten salt baths may contain potassium or sodium cyanide, a deadly poison. Handle the salt mixture with caution and watch for contamination from carburized metal pieces.
  • Do not wear oil-soaked clothing or put oily rags in your pockets.
  • Do not bring food or drink into areas where quench oils are stored or used.
  • Do not wear or take oil-contaminated clothing or equipment into areas where food or drink are consumed.
Document last updated on August 21, 2001

Copyright ©1997-2008 Canadian Centre for Occupational Health & Safety


Important Notices and Disclaimers
©CCOHS, 2008
Technical Support
 
Client Services
Products & services info
Inquiries Service
Answers to workplace questions
Webmaster
Website feedback