5Heat treatment and mechanical testing of AISI H11 steel

Sayyad Zahid Qamar*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Citations (Scopus)


Belonging to the class of chromium tool steels, AISI H11 possesses very good toughness and hardness, and is therefore suitable for hot metalforming jobs performed at very high loads. Mostly used in fabrication of helicopter rotor blades, H11 also has great potential as a die steel in hot-work forging and extrusion. This alloy steel can be heat treated to increase the service life and dimensional accuracy of the die and tooling. Main aim of the current investigation was to formulate an optimum heat treatment strategy for H11 steel, especially for hot work applications. High-speed milling and electric discharge machining were used to fabricate samples for tensile and impact testing. After various types of heat treatment (annealing, austenitizing, air cooling or oil quenching, single and double tempering), these samples were tested for hardness, toughness (impact), yield strength, tensile strength, and ductility. Microstructural analysis was also performed to analyze the effect of heat treatment on mechanical properties. As tempering temperature increases, hardness initially increases and then starts to gradually decrease; impact strength first decreases and then increases; and yield strength exhibits a fluctuating pattern of initial decline followed by an increase and another decrease. Even though H11 steel is highly suitable for both hot and cold-work, it is surprisingly not a common choice for metalworking dies and tools. Results presented here can encourage die designers and hot-work practitioners to explore the versatility of this tool steel, and to adopt appropriate heat treatment strategies for different applications.

Original languageEnglish
Title of host publicationKey Engineering Materials
PublisherTrans Tech Publications Ltd
Number of pages6
ISBN (Print)9783038354956
Publication statusPublished - 2015
EventInternational Conference on Machining, Materials and Mechanical Technologies, IC3MT 2014 - Taipei City, Taiwan, Province of China
Duration: Aug 31 2014Sept 5 2014

Publication series

NameKey Engineering Materials
ISSN (Print)10139826


OtherInternational Conference on Machining, Materials and Mechanical Technologies, IC3MT 2014
Country/TerritoryTaiwan, Province of China
CityTaipei City


  • H11 tool steel
  • Hardness
  • Microstructure
  • Optimum heat treatment
  • Tensile properties
  • Toughness

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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