During the day-to-day operation of heat treat departments, many habits are formed and procedures followed that sometimes are done simply because that’s the way they’ve always 
been done. One of the great benefits of having a community of heat treaters is to challenge those habits and look at new ways of doing things. Heat Treat Today‘s 101 Heat Treat Tips, tips and tricks that come from some of the industry’s foremost experts, were initially published in the FNA 2018 Special Print Edition, as a way to make the benefits of that community available to as many people as possible. This special edition is available in a digital format here.
Today we continue an intermittent series of posts drawn from the 101 tips. The tips for this post come from a variety of categories but all generally address safety or cost-saving ideas.
Heat Treat Tip #2
Avoid axle shaft cracks after induction tempering
Situation: In induction scan hardening of axle shafts, there was NO cracking occurred after scan hardening (case depth varies from 5 mm to 8 mm). Cracks appeared in the spline region after induction tempering.
Solution: Most likely, the cause of this problem is associated with a reversal of residual stress distribution during induction tempering. Reduce coil power for tempering and increase time of induction tempering. Multi-pulse induction tempering applying lower power density might also help. As an alternative, instead of modifying temper cycle, you can also try to reduce quench severity by increasing the temperature of the quenchant and/or its concentration.
Heat Treat Tip #4
Closed Loop Water System on Top
When designing a vacuum furnace installation with a closed loop water system, elevate the tank and pump about 9 feet, then cage the space underneath for thermocouple storage, spares, and tools. Saves shop floor space.
Submitted by AeroSPC
Heat Treat Tip #6
Don’t Be Cheap. Buy an IR Camera.
IR cameras have come way down in price—for a thousand dollars, you can have x-ray vision and see furnace insulation problems before they cause major problems—also a great diagnostic tool for motors, circuit breakers, etc. (And you can spot deer in the dark!)
Submitted by Combustion Innovations
Heat Treat Tip #7
An Engineer’s Design Checklist
When SCRs are involved in the design of a new piece of equipment, questions arise. Control Concepts Inc of Chanhassen, MN, offers a 20-point design checklist to help engineers who don’t specialize in power controllers. Good reading. Search for “design checklist” at the website.
Submitted by Control Concepts, Inc.
Heat Treat Tip #9
Question the Spec! Save Money!
Before you specify a heat treatment, stop and consider your options. Rather than reusing an old specification, ask the design engineer to determine the stress profile, and base the hardness or case depth on real stress data. Is this complicated? Maybe. But especially for carburizing, why pay for more depth than you need, and why take the risk of inadequate strength? The 21st century is here. We have ways to help with the math. Let’s move beyond guess and test engineering methodology.
Submitted by Debbie Aliya
