Research On High-temperature Mechanical Behaviors Of 304, 410S And E01 Stainless Steels

Thin strip casting has been the most concerned technology in many iron and steel industry, but the cracks in the stainless steel slab will seriously affect the follow-up processing, as well as the quality of the final product. The following defects, in hot-rolled coil such as the edge damage, edge cracks, will also make obvious effect in yield and economic benefits. In this paper, by the basic study of the high temperature mechanical properties and high temperature deformation behavior on the as-cast 304 austenitic stainless steel (304 stainless steel for short), 410S ferritic stainless steel (the 410S stainless steel), E01 low-nickel austenitic stainless steel (stainless steel referred to as E01) to provide the basic dates for the development of casting technology.The main contents of this paper are as follows:1. 304 stainless steel, 410S stainless steel and E01 Stainless Steel are tensile test from 300 to 1250℃high temperature with the universal tensile testing machine. With the temperature increasing, the strength of the three stainless steels is rapidly declining while reduction in area and elongation are having a trend to increase overall. Either 410S and E01 have a clear ductile-brittle transition point, which is respectively 950℃and 800℃.2. Observing and analyzing the organization of the evolution, the fracture morphology and the phase composition analysis of the three stainless steel with optical electron microscopy (OM), scanning electron microscopy (SEM) and X-ray analyzer (XRD).We can obvious observe that 5-ferrite is occurring and growing up together at 1150℃in 304 stainless steel. 410S stainless steel is entering the two-phase region at 800-950℃. 8-ferrite in E01 Stainless Steel is obvious spheroidizing at 1250℃.3. Simulation experiments were made on Thermechastor-W use of heat / power thermal simulation testing machine at the deformation temperature of 950-1250℃, strain rate of 0.01-2.5 s^-1, and the dependent variable is 0.5.The single-path hot compression test is for 304 stainless steel and 410S stainless steel . 304 stainless steel and 410S stainless steel for the apparent stress exponent (n). deformation activation energy (Q), respectively: n₃₀₄ = 5.13, n_410S=4.57, Q₃₀₄=464kJ/mol, Q₃₀₄=430kJ/mol, the thermal deformation equation as follows:4. The stress - strain curves of 304 and 410S stainless steel are all having the following laws: at the initial stage in the deformation, that is to say, when the strain is smaller, the stress increase rapidly, which is the so-called work-hardening, then the stress increases to a peak rapidly with the increase of the strain ; Increasing the strain future, flow stress decreased very little, that is, to enter the stage of steady-state flow.5. Observing and analysis the thermal deformation organizations of 304 and 410S stainless steel by optical electron microscopy (OM) ,we can drive a conclusion that: at a certain strain rate ,the higher the temperature the more conducive to the occurrence of dynamic recrystallization; and a certain temperature under the (more than dynamic recrystallization temperature), strain rate will help lower the occurrence of dynamic recrystallization. At the same deformed degree, the dynamic recrystallization grain size will grow up with the rising of deformed temperature and decrease with the increase of strain rate.