Effect of Solution Temperature on the Microstructure and Properties of 17-4PH High-Strength Steel Samples Formed by Selective Laser Melting

Pengcheng Huo,Hailin Wang,Zhanyong Zhao,Peikang Bai,Xiaofeng Li,Wei Zhang,Wenbo Du,Jianmin Li

doi:10.3390/met12030425

Abstract

Samples of 17-4PH high-strength steel were processed by selective laser melting (SLM) and solution-processed. The effects of the solution temperature on the microstructure and mechanical properties of the samples were studied. The 17-4PH high-strength steel is primarily composed of martensite, with a small number of austenite phases, and contains many dislocations. After the solution treatment, the grain size gradually increased, yielding typical martensite. The samples were subjected to an aging treatment after the solution treatment. Precipitates formed in the samples, conducive to improving their strength and hardness. The Vickers hardening and wear properties of the 17-4PH high-strength steel samples first increased and then decreased with increasing solution temperature. After the solution treatment at 1040 °C for 2 h and aging at 480 °C for 4 h, the Vickers hardening of the 17-4PH high-strength steel increased to 392 HV0.5, and the friction coefficient was approximately 0.6. These values were, respectively, 7% and 5% higher than those for the untreated samples.

Highlights

The 17-4PH high-strength steel is a low-carbon martensitic stainless steel containing nickel and copper that can be hardened by precipitation [1]
Owing to the melting point of this material, it can only be used for a long time at temperatures below 30 ◦ C [4,5]
As the TEM sample becomes thinner, perforations form in the fine grain at the boundary of the molten pool

Summary

Introduction

The 17-4PH high-strength steel is a low-carbon martensitic stainless steel containing nickel and copper that can be hardened by precipitation [1]. This stainless steel material has high strength and strong corrosion resistance [2,3]. It is widely used in medical devices, the chemical industry, automobile manufacturing, the military industry, the aerospace industry, and the nuclear industry. Owing to the melting point of this material, it can only be used for a long time at temperatures below 30 ◦ C [4,5]. The martensitic structure and the high hardness caused by precipitation hardening increase the processing difficulty of this material [6,7]

Results

Discussion

Conclusion