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Fig. 2.  The goal: a world-class heat-treat shop (Courtesy of ALD Thermal Treatment)


Audits of the heat-treat department, whether in a captive or commercial shop, are a critical part of any good quality program either as part of a self-assessment, an ISO program or compliance with an industry requirement (e.g., Nadcap, CQI-9, TS16949, etc.). We all recognize that audits are a necessary vehicle for continuous improvement. Instead of fearing what we’ll find, we should embrace the audit process. Let’s learn more.

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Fig. 1.  Balancing the productivity/quality teeter-totter

Why Audit?

What Does an Audit Look For?

In general, heat-treat audits look at people, methods, equipment and testing procedures to measure the overall success of a department’s quality. Specific areas of focus include:

  • General facts (e.g., company/department profile)
  • Capabilities (e.g., ability to meet customer requirements)
  • Instructions (e.g., recipes, records, processes in-control)
  • Sampling guidelines (e.g., testing methods and requirements)
  • Continuous improvement programs (e.g., plans, progress)
  • Specific compliance (e.g., audit questions/answers)
  • Nonconformance (e.g., major and minor deviations)
  • Corrective action (e.g., root-cause determination)

What Does an Audit Achieve?

Too often we are concerned with the heat-treat department’s capabilities, either in terms of overall capability, services we can offer to our customers or the size/quantity of equipment in our shops. More importantly, however, we need to focus on our limitations – we need to know what we can’t do and set our sights on overcoming these limitations. This is precisely what a good audit achieves.

Most audits should be done in two distinct phases: a general condition assessment and an equipment/process capabilities assessment. Each phase performs a different role.

Phase I: A general condition assessment asks questions such as:

  • Where are we today?
  • What is the true condition of our equipment?
  • Are we monitoring and controlling the right variables?
  • Are our maintenance practices adequate?
  • Do our methods and control systems measure up?

Phase II: A process/equipment capabilities assessment looks into:

  • Process recipes, cycle times and results
  • Historical record (e.g., defective parts and corrective actions, types of product failures being experienced and root-cause determination, etc.)
  • Safety and environmental conditions
  • Customer complaint resolution

What are the Audit Steps?

A typical audit looks to address the following issues (in sequential order) each time an audit is to be conducted:

  • Schedule a kick-off meeting to discuss the audit objectives, timing and report format and distribution. Be sure to include all necessary disciplines and assign an overall audit coordinator.
  • Assess the readiness of the heat-treat operation, controls and systems in place for an audit.
  • Plan, then test these systems to ensure proper operation.
  • Discuss all preliminary observations with management.
  • Draft realistic and achievable short-term and long-term corrective actions.
  • Discuss with management the draft audit report and their responses, if available, prior to release of the final audit report.
  • Follow up on critical issues raised in audit reports to determine if they have been successfully resolved.

Individual Job Audits

One of the best ways to understand if a general audit is necessary is to perform individual job audits. A job audit is a step-by-step review of all processes conducted on a given batch of parts to evaluate if they fully meet customer requirements. A good heat-treating job audit will cover items such as:

  • Incoming part inspection and material verification
  • Material specification review
  • Component part drawing/heat-treating specification reviews
  • Part fixturing/racking method
  • Procedure for recipe creation and overall process-cycle review
  • Equipment selection/capability
  • Process review (including atmosphere requirements)
  • Testing requirements/methods/capabilities/certifications
  • Shop paperwork – forms/record keeping
  • Operator and quality sampling/testing and acceptance criteria

Additional Audit Requirements

Areas such as data management and operator/maintenance personnel training (in accordance with SAE-ARP-1962) should not be overlooked. Critical questions need to be asked, including if the various heat-treat equipment has the ability to display, achieve, store and retrieve critical process data and if the company has a defined training program and is reinforcement training done on an annual basis?

Finally, companies should consider independent verification of their auditing practices. Personnel conducting such audits would observe processes being run; review equipment and methods in use; talk with supervisors, managers and engineers about policies and procedures; collect evidence that activities are as claimed; and verify operations, including outputs at the various steps.

Internal audits have broad-based objectives, including verification of items such as:

  • Special procedures or tests
  • Product characteristics and performance
  • Implementation of procedures to match the requirements
  • Defects or nonconformities and if are they being addressed
  • Training, equipment capabilities and process settings

By comparison, external auditors look to verify that:

  • All appropriate requirements are being followed, including supplier processes and calibration procedures, heat-treatment methods and maintenance activities
  • Supplier product/service characteristics or performance measures
  • Conformance to contract requirements
  • All nonconformities have been addressed
  • Material is as specified, and all sources are traceable

Audit Follow-Up

Don’t forget to conduct a follow-up audit within six months after the initial (internal or external) audit has taken place and the audit report has been issued. This should be scheduled before the initial audit takes places. The purpose of this follow-up is to critically evaluate if corrective action has been taken on the audit issues reported in the original report.

In Conclusion

The most common excuse for not performing an audit is that we are too busy. However, it always seems there is enough time to do the task over again. Let’s do it right the first time and every time. Perform an audit, find areas where improvement is needed and take the necessary corrective action. You’ll be happy you did. IH