Effect of heat treatment on mechanical properties of H11 tool steel

• Autorzy: Qamar S. Z.
• Języki publikacji: EN

Abstrakty

EN

Purpose: AISI H11 is a special alloy steel, categorized as chromium tool steel. Because of its high toughness and hardness, it is well suited for hot work applications involving very high loads. Typical applications are hot-work forging and extrusion dies, helicopter rotor blades, etc. For longer life and higher design accuracy, properties of this type of tool steel can be improved by various types of heat treatment. Current work reports and analyzes results of mechanical testing performed on variously heat treated H11 steel samples, to arrive at an optimum heat treatment strategy for hot work applications. Design/methodology/approach: Tensile and impact test specimens were fabricated using precision milling and EDM. These samples were subjected to various heat treatment sequences, consisting of annealing, hardening, air and oil quenching, and tempering at different temperatures. Heat treated samples were then mechanically tested for hardness (Rockwell), impact toughness (Charpy), and tensile properties (yield strength, ultimate strength, ductility). Findings: Mechanical testing of H11 samples revealed that with increasing temper temperatures: (a) hardness first increases to a maximum and then gradually decreases; (b) impact toughness first decreases to a minimum and then increases; (c) yield strength first decreases, then increases, and then increases again; (d) ultimate strength first increases to a maximum and then steadily decreases; and (e) ductility (% elongation) gradually decreases till 600şC, and then increases rather sharply. Practical implications: Though a very promising candidate for hot-work applications, H11 steel is not commonly used for die and tool making. Results of this study can provide die designers and users in the metalworking industry with good guidelines to select proper heat treatment strategies to use H11 steel for various applications. Originality/value: Very little information is available in published literature about mechanical properties of H11 steel, especially after different types of heat treatment. Results from this study can fill some of this gap.

Słowa kluczowe

EN

tool steel; heat treatment; hardening; quenching; tempering; mechanical properties

PL

stal narzędziowa; obróbka cieplna; utwardzanie; hartowanie; odpuszczanie; właściwości mechaniczne

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2009
• Tom: Vol. 35, nr 2
• Strony: 115--120
• Opis fizyczny: Bibliogr. 20 poz., rys., tabl.

Twórcy

autor

Qamar S. Z.

• Mechanical and Industrial Engineering Department, Sultan Qaboos University, Al Khoudh 123, Box 33, Oman,

Bibliografia

• [1] J. Kaszynski, R. Breitler, How the Steelmaking Process Influences the Properties of Hot Work Die Steels, Technical Paper - Society of Manufacturing Engineers CM02-216 (2002) 1-12.
• [2] ASM International, ASM Handbook Volume 1: Properties and Selection - Nonferrous Alloys and Special Purpose Materials, 10th edition, American Society for Metals, Metals Park, Ohio, 1990.
• [3] J. R. Davis ASM Specialty Handbook: Tool Materials, ASM International, Materials Park, Ohio, 1995.
• [4] G. A. Roberts, G. Krauss, . Kennedy, Tool Steels, 5th edition, American Society for Metals, Metals Park, Ohio, 1998.
• [5] J. Szumera, The Tool Steel Guide, Industrial Press, New York, 2003.
• [6] W. E. Bryson, Heat Treatment, Selection, and Application of Tool Steels, 2nd edition, Hanser Gardner Publications, Cincinati, 2005.
• [7] B. Fnides, M. A. Yallese, H. Aouici, Hard Turning of Hot Work Steel AISI H11: Evaluation of Cutting Pressures, Resulting Force and Temperature, Mechanic 72/4 (2008) 59-63.
• [8] Da Klobcar, Ja Tušek, Bb Taljat, Thermal Fatigue of Materials for Die-Casting Tooling, Materials Science and Engineering A 472 (2008) 198-207.
• [9] G. Cornacchia, M. Gelfi, M. Faccoli, R. Roberti, Influence of Aging on Microstructure and Toughness of Die-Casting Die Steels, International Journal of Microstructure and Materials Properties 3 (2008) 195-205.
• [10] M. Pellizzari, M. Zadra, A. Molinari, Tribological Properties of Surface Engineered Hot Work Tool Steel for Aluminum Extrusion Dies, Surface Engineering 23/3 (2007) 165-168.
• [11] Oa Barrau, Ca Boher, Rb Gras, Fa Rezai-Aria, Analysis of the Friction and Wear Behavior of Hot Work Tool Steel for Forging, Wear 255 (2003) 1444-1454.
• [12] D. Nolan, V. Leskovsek, M. Jenko, Estimation of Fracture Toughness of Nitride Compound Layers on Tool Steel by Application of Vickers Indentation Method, Surface and Coating Technology 201 (2006) 182-188.
• [13] GE Totten (ed) Steel Heat Treatment Handbook; Vol 1: Metallurgy and Technologies; Vol 2: Equipment and Process Design, 2nd edition, 2007, CRC Press, Boca Raton.
• [14] ASM International, ASM Handbook Volume 4: Heat Treating, American Society for Metals, Metals Park, Ohio, 1991.
• [15] ASTM E18, Standard Test Method for Rockwell Hardness of Metallic Materials, American Society of Testing and Materials, 2008.
• [16] ASTM E23, Standard Test Method for Notched Bar Impact Testing of Metallic Materials, American Society of Testing and Materials, 2007.
• [17] ASTM E8, Standard Test Method for Tension Testing of Metallic Materials, American Society of Testing and Materials, 2008.
• [18] S. Z. Qamar, A. K. Sheikh, A. F. M Arif, A CVN-KIC Correlation for H13 Tool Steels, International Journal of Materials and Product Technology 33/4 (2008) 421-432.
• [19] S. Z. Qamar, A. K. Sheikh, A. F. M Arif, T. Parif, Regression-Based CVN-KIC Models for Hot Work Tool Steels, Materials Science and Engineering A 430 (2006) 208-215.
• [20] A. F. M. Arif, A. K. Sheikh, S. Z. Qamar, K. M. al-Fuhaid, A Study of Die Failure Mechanisms in Aluminum Extrusion, Journal of Materials Processing Technology 134/3 (2003) 318-328.