Papers by Keyword: Rolling Temperature

Abstract: In this study, high-cost Cr and Ni components of 202 austenitic stainless steel were reduced, low-cost Mn was added, and the amount of martensite and the mechanical properties were evaluated according to the rolling temperature and rolling degree. Part of the austenite was deformed by rolling into α′-martensite. As the rolling degree was increased, more martensite was generated; and at the same rolling degree, as the rolling temperature decreased, more martensite was generated. Up to a rolling degree of 33 %, the amount of martensite rapidly increased; thereafter, it gradually increased. In particular, the amount of martensite at a rolling temperature of-196 °C was similar to that after the rolling degree of 33 %. As the rolling temperature decreased and the rolling degree increased, both the Vickers hardness and tensile (yield) strength increased, while the elongation rapidly decreased.

Abstract: The effect of enter rolling temperatures on the grain size and toughness was investigated in Q345E H-beam steels. The experimental results shown that the grain size exhibited a complicated phenomenon with rolling temperature instead of refining as the temperature decreased as expected. It would be interpreted by the behaviors of deformation and recrystallization in austenite during rolling. The toughness is not only depended on the average grain size but also on the distribution of grain size as well as morphology of pearlite. The toughness would be decreased by the mixed grain size.

Abstract: In the hot rolling process calibrated rolls are used for the production of various simple and complex profiles. Rolling temperature is an important parameter of technological process which has great influence on energy costs, scale formation and rolling forces. In order to reduce the cost of energy, an analysis of the rolling temperature influence on fatigue life of the rolls has been carried out.The fatigue life estimation is carried out according to the fatigue life stress concept based on the local stress.Stress spectra in critical areas are determined for three different temperatures. The analysis shows that although lowering of the initial rolling temperature causing decreasing the fatigue life of the roll, the stresses caused by the rolling at thelowest temperature should not lead to roll fracture.

Abstract: Single pass hot rolling was adopted to form Goss texture at subsurface layer after hot rolling in twin-roll cast oriented silicon steel strip. It is found that the intensity of Goss texture is affected obviously by rolling reduction and finishing temperature. Goss texture originates from adjacent texture components, and rarely from {100} component. An appropriate rolling temperature and reduced initial {100} texture are beneficial for generating sharp hot rolling Goss texture at relatively low reduction.

Abstract: Effect of rolling temperature and cooling velocity on organization properties of T700 and the working load of the coiler was investigated with Gleeble-3800 Thermal/Mechanical Simulator. The results of this experiment show that the working load of the rolling machine will be increase with the reduction of the rolling temperature. The best rolling temperature is 550~600°C and the best holding time after rolling is one hour.

Abstract: Mg-2.0Zn-0.8Gd (wt. %) alloy was rolled consecutively at different temperatures. The influence of rolling temperature and annealing process on the microstructure, texture and mechanical properties of the sheet were investigated. A deformation microstructure consisting of many intersected twins and a few dynamic recrystallization grains, and a basal texture with basal poles tilting about ± 10-15° from the normal direction towards the rolling direction were observed in the as-rolled sheet after 4 consecutive rolling processes. Static recrystallizaiton took place in the sheet after annealed above 300 °C. The annealed sheet exhibited a uniform microstructure and a non-basal texture with basal poles tilting about ± 38-43° from the normal direction towards the transverse direction. The annealed sheets exhibited higher ductility about 32% along the rolling direction and 40% along the transverse direction comparing with the as-rolled sheets. The static recrystallization during annealing process was helpful to modify the texture as well as the dynamic recrystallization during rolling in the RE-containing alloys.

Abstract: The silicon steel was rolled to 95% reduction at 20°C, 400°C and 600°C, and subsequently annealed at different temperatures to obtain complete recrystallization microstructure without appreciable grain growth. The effects of rolling temperature on through-thickness deformation and recrystallization textures were investigated by ODF analysis. The deformation textures are all composed of α- and γ-fiber, whereas α-fiber and {111}﹤110﹥ decrease and {111}﹤112﹥ increases with the increasing rolling temperature. Through-thickness recrystallization texture varied significantly, a strong partial γ-fiber spreading from {111}﹤112﹥ or {554}﹤225﹥ to {111}﹤134﹥ and {114}﹤481﹥ are developed in steel sheet rolled at 20°C and 400°C, while a dominated η-fiber peaked at {310}﹤001﹥ is formed between surface and quarter thickness in steel sheet rolled at 600°C. The different recrystallization textures can be ascribed to the profuse shear band at 600°C compared with the microstructures at 20°C and 400°C.

Abstract: In this article, the Al/Ni reactive multilayer foils that can be used for joining materials in an efficient and energy-saving way were prepared by a hot rolling method, during which the Al/Ni multilayer foils were kept in furnace at a certain temperature for a period before the multilayer foils were rolled for each pass. After the cold rolling and hot rolling procedure at the temperature of 200 oC and 300 oC, no reaction between Al and Ni could be detected. The effect of rolling temperature on the self-propagating high temperature synthesis (SHS) reaction of the Al/Ni multilayer foils was investigated. As the rolling temperature rose to 300 oC, the SHS reaction of the Al/Ni multilayer was hard to be ignited and was even quenched before the SHS reaction completed. The XRD patterns and SEM images results demonstrated that the higher temperature increased the deformation of the samples during the rolling passes so the Ni particles increased, and thereby led to the decrease of the mix homogeneity of Al and Ni foils.

Abstract: Effect of superheat and initial rolling temperature on the morphology and distribution of sulfide in non quenched and tempered free cutting steel 30MnVS has been studied by optical microscope and scanning electron microscope. Results show that proper superheat and initial rolling temperature can turn rod-shaped sulfide into massive or globular sulfide，to alleviate sulfide segregation and pro-eutectoid ferrite distribution along the boundary of pearlite clusters in 30MnVS , increase the intragranular ferrite content and optimize the structure of continuous casting slab.

Abstract: Effect of the severe deformation by multi-pass rolling on microstructure and tensile properties was analyzed in terms of rolling temperature, plate thickness, and cooling rate for a modified API X65 steel containing B. The plates, 80 and 50 mm thickness, were rolled six times by 20%/pass (total 75%) to 20 and 12 mm, at 1023 K of unrecrystallized γ region or 973 K of intercritical (α+γ) region, and then quenched in water or oil. All specimens except one oil-quenched condition showed relatively high UTS 700-830 MPa and the continuous yielding(YR～0.6), typical mode of the (ferrite + martensite (bainite)) dual phase microstructure. In contrast, one oil-quenched specimen with the 973 K-20 mm condition, exhibited the discontinuous yielding (YR～0.8), indicating that the microstructure basically consists of ferrite plus pearlite, as well as a relatively low UTS 660 MPa. The degree of deformation really occurring within materials, i.e., strain hardening seems to be enhanced with a decrease in deformation temperature. As the degree of deformation increases, the remaining austenite, not dynamically transformed to fine ferrite, becomes increasingly unstable. A lower hardenability of this remaining austenite thus would lead to a higher possibility to transform into the (ferrite + pearlite) structure of lower strength rather than the (ferrite + martensite (bainite)) of higher strength.