AISI H13 Hot-Work Steel with Hard Chromium Plating Thermal Fatigue Behavior Evaluation

Abstract

A hard-coating on hot work tool steel can be used to obtain higher corrosion resistance, as well as better wear resistance. This study investigates the thermal fatigue performance of AISI H13 hot work tool steel with and without hard chromium plating. Treated specimens were characterized using microstructural analysis, X-ray diffraction analysis and microhardness measurement. The thermal fatigue test is based on cyclic induction heating and water cooling. The specimen was heated to the maximum surface temperature of 670°C followed with water injection to bring the specimen down to a minimum temperature of 25°C. The thermal fatigue testing in this study was conducted using 500 cycles. A vacuum heat treated specimen with a hardness of 47 HRC was used as the reference material. The hard chromium plated layer with a thickness 35 μm had a hardness of 930 HV0.1. The damage factor, defined as crack depth × crack width, of quenched and tempered H13 specimens and hard chromium plated specimens were 800 and 1760, respectively. The damage factor evaluation verified the vacuum heat treated specimen thermal fatigue resistance is superior to that of the hard chromium plated specimen.

The Effect of Heat Treatments on the Fatigue Strength of H13 Hot Work Tool Steel

“…Hardness values also show a significant increase after quenching, which can be explained as a result of the dissolution of the most carbides and their being in solid solution form in the martensitic structure (Figure 3 and Figure 4). Tempering, however, causes slight softening of the material, due to the density reduction of microstructural defects such as dislocations [4,24,26] . Specimens which were tempered at 550 °C for two hours (2 nd Sequence) had a fatigue strength of 630 MPa which was close to that of specimens which were solely subject to quenching (1 st Sequence).…”

“…In the context of alloyed steel and hot metal forming, the most important component of any process usually reveals to be the die, since its requirement of exceptional precision and reliability increase the cost. Dies generally experience rather high cyclic temperatures variations and mechanical loading; they work in erosive/corrosive environment [2,3] and consequently suffer mechanical and thermal fatigue [4,5,6,7] . In an attempt to prolong their working life, improve efficiency and reduce cost of processing; they are produced of hot work steel material.…”