A comparative study on the hot deformation behavior of 410 stainless and K100 tool steels

Hot deformation characteristics of 410 stainless and K100 tool steels were compared through hot compression tests in temperature range of 800-1200 degrees C and strain rates of 0.001-1 s-1. Carbon content is the major difference between the studied steels. Its higher content in K100 leads to a considerable amount of carbide particles even after reheating and through hot working; whereas, they are absent in 410 due to its lower C content. The flow curves of K100 showed fast work hardening at low strain levels and distinct peaks implying the occurrence of DRX. However, the flow curves of 410 exhibites more gradual work hardening and the peaks appeared at larger strains. It was concluded that dynamic recrystallization (DRX) in K100 precedes that in 410. However, the Avrami model suggested that DRX in 410 is faster than that in K100. Constitutive analysis showed that K100 has higher apparent activation energy at the peak but lower at strain of 0.5. The primary and dynamically precipitated carbides were found responsible for the higher deformation resistance of K100 at the peak. Observations by EBSD confirmed that discontinuous and continuous DRX are the dominant recrystallization mechanisms in 410 and K100, respectively. The higher internal deformation energy due to the existence of fine carbide particles is the major reason for the start of DRX at lower strains in K100. However, despite the sluggish nature of continuous DRX in K100, discontinuous DRX in 410 proceeds faster.