Heat treatment is an investment that delivers huge returns
Tool steels must provide consistent performance over time and withstand the challenges of the production environment including wear, plastic deformation, fracture, and in-service high temperature. When premature tool failures occur, tremendous losses result with production delays, quality issues and costly tool repair and replacement. Generally speaking, it is estimated that 60% of premature tool failures are due to poor-quality heat treatment.
Proper heat treatment is vital to achieving high performance and preventing these expensive failures. For example, heat treatment quality can be the difference between a die-casting insert producing 100,000 aluminum transmission cases and another that produces only 10,000 units. Best practice heat treatment provides better mechanical properties and consequently delivers significant reduction in production costs and downtime.
While heat treatment quality plays a key role in tool performance and significantly saves costs on unexpected failures, the importance of heat treatment is often overlooked due to its comparatively low cost and the mistaken belief that hardness alone predicts performance. Such misunderstandings can compromise critical design properties of your steel, ultimately giving rise to premature failure.
This article provides an overview of heat treatment considerations to illustrate its true value: producing a long-lasting, high-performing tool that maximizes the return on your investment.
Physics set the timeline
In planning your tool production process, it’s imperative to understand the physical constraints determining the time needed to perform proper heat treatment. The material transformations necessary to deliver a high-performing tool require several carefully timed incremental steps. Although there are ways to achieve a desired hardness with a faster turnaround time, skipping steps for a quicker turnaround will compromise other mechanical properties and leave the tool vulnerable to failure. Therefore, heat treatment quality should never be sacrificed for turnaround as doing so sacrifices the quality and performance of the tool. Figure 1 illustrates a typical heat treatment cycle.
Questions to Ask Your Heat Treatment Partner
- What is the steel producer’s suggested course of heat treatment?
- What special considerations are necessary for my tool’s application to avoid premature failure?
- What other properties will you optimize in addition to hardness?
- Is stress relieving required for my tool?
- How much machining stock should I leave on my tool before hardening?
- What else should I consider in the manufacturing process to support effective heat treatment?
- What measures will you take to minimize dimensional changes during the hardening process?
- What is your recommended quenching process for my particular tool?
- How many tempers do you recommend for my tool based on the intended application?
- What is a realistic timeline to achieve my goals for heat treatment?
*Be sure to have this conversation before manufacturing begins!