Grain Refining and Texture Control of Nonferrous Metals through High Speed Hot Rolling

高速热轧有色金属晶粒细化和织构控制

• 批准号: 02650496
• 负责人: SAKAI Tetsuo
• 金额: $ 1.47万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650496/
• 关键词: Hot Rolling; Recrystallization; Shear Strain; Preferred Orientation; alpha + beta Titanium Alloy; beta Titanium Alloy; Transformation Texture; Copper; 集合組織; α+βチタン合金; T方位

The effects of hot rolling condition on the structure of quenched sheet of Ti-6Al-4V alloy, Ti-15V-3Cr-3Sn-3Al alloy and oxygen free copper are investigated. In high speed hot rolling of Ti6Al-4V sheet, shear deformation produces a severely sheared region beneath the surface. The shear strain increases with increasing rolling temperature and decreases with reducing friction coefficient at the roll surface. Extremely fine recrystallized equiaxed alpha-grains appear in the severely sheared region of the sheet rolled in alpha + beta region. These fine alpha grains grows to diameter of 3mum on annealing at 1173K for 3.6ks. In the severely sheared region of the sheet rolled at beta region, extremely fine acicular alpha'-martensite transformed from fine recrystallized beta grains appears, which does not form equiaxed structure after annealing. In the central layer of the sheet where shear strain is negligibly small, lamellar structure develops. The preferred orientation of alpha phase in the … More severely sheared region changes with rolling temperature. In the sheet rolled at 1323K(beta region), only the transformed texture from (110)<001> orientation through the Burgers' relation, which is the shear texture of bcc metals known as Goss texture. In the severely sheared region of the sheet rolled in alpha + beta region, the texture consists of main components of transformed texture from shear texture of beta-phase and shear texture of alpha-phase (<0001>*ND). The intensity of the shear texture of the sheet rolled in alpha + beta region is weaker than that of the sheet rolled in beta region. After annealing, intensity of shear texture increases and T-texture(<0001>*TD) develops. In hot rolling of Ti-15V-3Cr-3Sn-3Al sheet, shear deformation also accumulates beneath the surface to form severely sheared region and a band of extremely fine recrystallized grains appears. The average grain size of recrystallized grains decreases with decreasing rolling temperature and with decreasing holding time af ter rolling. Grain size is 3mum after hot rolling and grows to 10mum on anneal ing af ter cold rolling. The microstructure of the copper sheet quenched immediately after high speed hot rolling changes from wrought grains to recrystallized grains with increasing rolling temperature and reduction. From the optical and TEM micrographs, it is concluded that static recrystallization occurs within very short interval after hot rolling. Less

研究了热轧工艺条件对Ti-6Al-4V合金、Ti-15 V-3Cr-3Sn-3Al合金和无氧铜淬火板组织的影响。在高速热轧过程中，Ti6 Al-4V板材的剪切变形在表层下产生了严重的剪切区。剪切应变随轧制温度的升高而增大，随辊面摩擦系数的减小而减小。在α + β区轧制时，在剪切剧烈区出现了极细的再结晶等轴α晶。这些细小的α晶粒在1173 K下退火3.6ks后生长到直径为3 μ m。在β区轧制的板材，在严重剪切区出现由细小再结晶β晶粒转变的极细针状α ′马氏体，退火后不形成等轴组织。在剪切应变小到可以忽略不计的板的中心层中，形成层状结构。α相的择优取向 ...更多信息 严重剪切区随轧制温度的变化而变化。在1323 K（β区）轧制的板材中，只有（110）取向的织构<001>通过Burgers关系转变为bcc金属的剪切织构，称为Goss织构。在α + β区轧制的板料的严重剪切区，织构主要由β相剪切织构和α相剪切织构（*ND）的转化织构组成<0001>。在α + β区轧制的板材的剪切织构强度弱于在β区轧制的板材。退火后，剪切织构强度增加，T织构（<0001>*TD）发展。在Ti-15 V-3Cr-3Sn-3Al板材的热轧过程中，剪切变形也在表层下累积，形成严重剪切区，并出现一条极细的再结晶晶粒带。再结晶晶粒的平均尺寸随轧制温度的降低和轧后保温时间的缩短而减小。热轧后的晶粒尺寸为3 μ m，冷轧后退火时晶粒尺寸增长到10 μ m。随着轧制温度的升高和变形量的增加，高速热轧后立即淬火的铜板组织由变形晶粒向再结晶晶粒转变。从光学显微镜和透射电镜照片，得出结论，静态再结晶发生在很短的时间间隔后，热轧。少