The Heat Treatment and Cutoff Simulation found on the home page provides a realistic setting for practicing statistical process control. Although the simulation is based on one specific industry, the statistical techniques have wide use in other settings. The following background information will help you understand the heat-treating process at Key Knife Inc. On-site information came from discussions with Key Knife staff, particularly Jose Peralta for operations and quality assurance, and Danko Munetic for heat treating. Mark Huntington, metallurgy instructor at Lane Community College, reviewed the heat treating pages. Technical information came from Metallurgy Theory and Practice by Dell K. Allen. Steel characteristics are from Treatment of Tool Steel by the Uddeholm Corporation and from Uddeholm information sheets. Any errors of fact are purely those of the project authors. Some aspects of the heat-treating process have been omitted or simplified in order to make the topic understandable. Key Knife, Inc. makes blades used in wood products manufacturing and recovery.

1. Run the machinery to produce the number of parts you choose. See the web pages Simulation User's Guide.

2. Get production data using the program Heat Treatment and Cutoff Simulation. You will obtain measurements of blade length and hardness.

3. Use statistical tools such as Excel to analyze the production data.

4. Use your analysis to diagnose and correct problems with the machinery or identify problems with machinery, methods, materials, or measurements. These methods are reviewed in the web pages
Review of Statistics for Statistical Process Control.

The two main steps in heat treating used at Key Knife are hardening and tempering. The steel used to make chipper blades is heat-treated to give it the right mix of hardness and toughness. Hardness refers to the resistance to wear; toughness to the ability to absorb impact energy without breaking. The blades must also emerge from heat treatment the right size and without warping; otherwise, the blade will not fit correctly in the customer's machines. Steel is an alloy of iron with a small percentage of carbon and trace elements such as manganese and chromium. Since carbon and iron do not easily mix or even stay mixed at different temperatures, heating and cooling must be carefully controlled to keep the desired molecular structure. Time and temperature are manipulated to produce blades that are hard, tough, and dimensionally correct.