Hot isostatic pressing method for laser additive manufacturing of 24CrNiMo alloy steel

Abstract

The invention provides a hot isostatic pressing method for laser additive manufacturing of 24CrNiMo alloy steel. The method comprises the following specific steps: (1) selective laser melting: carrying out process optimization on a selective laser melting technology according to a forming state, sample surface flatness, pores and cracks, determining process parameters, carrying out selective laser melting by using spherical 24CrNiMo alloy steel powder with the particle size of 20-80 microns, and preparing a formed SLM 24CrNiMo alloy steel sample; and (2) hot isostatic pressing: determining the phase transition point temperature, the defect problem and the density of the formed SLM 24CrNiMo alloy steel sample, determining hot isostatic pressing process parameters, and performing hot isostatic pressing treatment on the formed SLM 24CrNiMo alloy steel sample, wherein the process parameters are that heat preservation is conducted for 1-4 h at the temperature of 780-830 DEG C, the pressure is 100-200 MPa, and slow cooling is conducted at the speed of 5-15 DEG C / min. The advantages of a short preparation period, low production cost, convenience in preparation of gradient component samples, easiness in improvement of material performance and the like of laser additive manufacturing are utilized for preparing the formed sample of the 24CrNiMo high-performance alloy steel, and the structure, compactness and toughness are improved through hot isostatic pressing post-treatment.

Description

technical field [0001] The invention relates to the technical field of additive manufacturing, in particular to a hot isostatic pressing method for laser additive manufacturing of 24CrNiMo alloy steel. Background technique [0002] The speed and load of the train are constantly increasing recently, and the current running speed can reach 380km / h, and the load is greater than 60 tons. Therefore, higher requirements are put forward for the stability and toughness of the train brake disc. Brake disc is a key part of the safe braking of high-speed trains. The heat dissipation ribs of the core require high strength and toughness, while the surface part requires high hardness and wear resistance. Traditional casting, forging and other manufacturing processes have problems such as complex preparation process and low utilization rate of materials; they are easily deformed by external force and heat treatment residual stress during processing; cracking and failure are prone to occur ...

AI Technical Summary

Problems solved by technology

Traditional casting, forging and other manufacturing processes have problems such as complex preparation process and low utilization rate of materials; they are easily deformed by external force and heat treatment residual stress during processing; cracking and failure are prone to occur in harsh service environments in alpine regions

The traditional manufacturing process is difficult and costly when preparing materials with high precision and shape requirements. Therefore, a hot isostatic pressing method for laser additive manufacturing of 24CrNiMo alloy steel is developed to overcome the above problems. The selective laser melting technology is suitable for production , followed by hot isostatic pressing can further improve the structure and performance

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