2
BOX 232 • MINNEAPOLIS, KS • 67467 HUYETT.COM • 785-392-3017 Prices, materials, dimensions, tolerances, designs, and grades subject to change without notice. © 2016 G.L. Huyett [email protected] • FAX 785-392-2845 98 TOOL STEEL FEATURES Design Considerations Tool Steel Grades Characterized by their durability, hardness, price, and ability to withstand shock without deforming, tool steels are used to cut, press, extrude, or stamp other metals. After being worked, they may be hardened to increase wear resistance and strength. Grades are specified by the American Iron and Steel Institute (AISI), the Society of Automotive Engineers (SAE), or the American Society for Testing and Materials (ASTM). For more information, see Tool Steel Comparison on page 105. ¢¢¢ COMPARATIVE COST low cost Water-hardening tool steel is used more often than oil- or air-hardening tool steels ¢ ¢¢ W1 O1 A2 DURABILITY resistance to deformation at elevated temperatures (also known as red-hardness) HEAT TREATING After machining, steel is heat treated and quenched, depending on the type of steel used, to increase toughness and strength Tool steels are defined by their dimensional stability, wear resistance, toughness, hot hardness, and machinability. Severe conditions – high temperatures, heavy loads, or corrosive environments – require higher alloy and carbon contents. Hot Work Steels Feature high hot yield strength, toughness, high red-hardness, wear resistance, erosion resistance, and resistance to softening in temperatures up to 675°C (1,247ºF). H1 - H19 Medium carbon content with 5% chromium. Can be through hardened to HRC 40-55 with little distortion. Requires oil quenching. H20 - H26 Low carbon content with 9% – 18% tungsten and 3% – 4% chromium. Extra resistant to softening, more prone to brittleness, working hardness to HRC 45-55. To minimize scaling, quench in oil or salt. H41 - H43 Low carbon content with 8% molybdenum along with chromium, tungsten, and vanadium. Water-Hardening Steels W1 - W3 Most common. These general purpose, low- cost, medium to high carbon (0.60% – 1.3%) steels are easily machined, or formed. They can be case hardened by heat treating up to HRC 68. Overall, they are more brittle and more susceptible to cracking or warping Cold Work Steels Frequently used for making cold working tools for applications under 200ºC (392ºF). Higher amounts of chromium reduce distortion during heat treatment. Feature high hardenability, high toughness, and high abrasion, impact, and wear resistances. A2 - A10, Air - Hardening Medium alloy composition with 1% – 6% carbon and up to 5% chromium. Has the least tendency to crack during hardening. Considered a mid-range grade between oil- hardening and shock resistant grades. Do not quench in oil or water. O1 - O7, Oil - Hardening A low alloy/high carbon (0.85% – 1.55%) steel with manganese, chromium, and molybdenum. Quenched in oil to produce high wear resistance and hardness between HRC 56-62. D2 - D7, High Carbon, High Chromium Contain 1.4% – 2.3% carbon and 12% – 14% chromium along with molybdenum, cobalt, and vanadium. Often thought of as stainless or semi-stainless, but corrosion resistance is limited due to high chromium and carbon. Wear resistant, but not as tough as low alloy steels. than other steels. Best suited for small parts and working conditions up to 150ºC (302ºF). High-Speed Steels (HSS) Designed for high speed metal cutting and machining operations. Features hardenability to HRC 60-70, high heat resistance for red-hardness up to 500ºC (932ºF) enables sharpening without damaging material, and reasonable toughness. M1 - M47 Contain molybdenum as a primary alloying element that increases resistance to softening at elevated temperatures. Shock-Resistant Steels S1 - S7 Contain medium carbon content from 0.40 – 0.55%, 1% – 2% silicon, or up to 3% nickel. As their name suggests, they have good wear/abrasion resistance and resist shock at low to medium temperatures, with high strength and toughness. Can achieve HRC 58-60. *Limited warranty for surface finish: 30 days from date of shipment. See page 12 for details.
