HEAT TREATMENT, SELECTION, AND APPLICATION OF TOOL STEELS

Title: HEAT TREATMENT, SELECTION, AND APPLICATION OF TOOL STEELS

Author: Bill Bryson
Publisher: Modern Machine Shop Publications/Hanser Gardner Publications, Cincinnati, OH 1997
ISBN: 1-56990-238-0
198 pages, 20 chapters and an index

If you want to get serious about heat treating, here is the book to raise you to the next level. Jack Andrews, in THE NEW EDGE OF THE ANVIL, and Randy McDaniel in THE BLACKSMITH PRIMER, have built the foundation. They have provided the basics. Bryson, an Advisor in Metals (AIM), starts the preface with the statement “This is not a book about metallurgy, but a book that describes in simple terms what happens to metal during heat treatment.” He states his goal and I believe he pretty well delivers it.

This book is actually written for tool room machinists that have access to high tech equipment, like time/temperature controlled furnaces, and use a wide variety of specialty steels; and for knife makers who take their “heat treating” very seriously. However, the average blacksmith who is making “blacksmith’ tooling can gain a lot from this book.

The book starts with a good, non-technical description of what steel is and what makes a tool steel. Next he talks about the equipment that would be used in a tool room heat treatment setting. Now we get to the heart of the book, in Chapter 5, he walks us through a very detailed, step by step, description of heat treating a piece of D2 tool steel. Chapters 6-13 then take each of the following steels: A2, A6, H13, S7, M2, 4140, O1, and W1, and explains how the heat treatment of each of them differs from the process described for D2. Chapter 14 covers the topic of “CRYOGENIC” in a heat treating setting. He includes a fairly basic do-it-yourself setup using dry ice, kerosene and a Styrofoam freezer chest. This process will allow you to cryogenically treat your tool steel at negative 120 degrees F/negative 84 degrees C.

Chapter 19 is especially useful. In it, Bryson describes how to select a tool steel to perform a particular job. There is an especially useful diagram which shows which of the various tools steels are best suited for general use vs. hot work vs. shock resistance vs. wear resistance. As blacksmiths we are most interested in the characteristics: hot work and shock resistance. The steels that fall in to this range are:H21 (best for heat resistance), H19, H13, A8, H12, H11, S5, S1 S7(best for shock resistance). This tells us that H11 or H12 are the best compromise between heat resistance and shock resistance. However, if heat resistance is paramount that H21 is needed and if shock resistance is most important in the tool, then S7 should be used. The only problem is that H11, H12, and H21 are not commonly mentioned as being “blacksmith friendly”. However, S7 and H13 are.

In Chapter 20, there are tables for about 45 different tool steels, listing their chemical composition, pre-heat temperature, quench temperature, and the ROCKWELL C obtained at various tempering temperatures. For example: O1 tool steel should have a pre-heat of 1200 degrees F.; quench at 1475 degrees F. As quenched O1 will give 66-ROCKWELL C; 300 degrees gives 63 down to a temper at 600 degree giving 54-ROCKWELL C.

If you are serious about your tool or knife making, then this book is a “must have”. It is very readable, with many charts and tables. Chapters 6-13 tend to be somewhat repetitive of the material presented in Chapter 5, but the differences are critical for the different tool steels.

I purchased this book from ENCO (a machine tool supply company), on sale for about $25. (normally lists for $31.95). AMAZON.com lists the book for $34.95, but had someone selling new copies for $24.93 in the new/used book section.

Book review by Albin Drzewianowski

-- AlbinDrzewianowski - 18 Dec 2007