Measurement and prediction of plastic anisotropy in deep-drawing steels

R-values and yield stresses were measured as a function of inclination with respect to the rolling direction on 15 steels selected from four basic types [high-strength low-alloy (HSLA), Al-killed drawing quality (AKDQ), interstitial-free (IF), and rimmed]. Orientation distribution functions (ODF’s) were also determined for these steels, using both X-ray and neutron diffraction techniques. The series expansion method was employed for predicting the plastic anisotropy of the rolled sheets. Comparison with the experimental measurements indicates that the “pancake” relaxed constraint model is a more accurate predictor of behavior than the Taylor, Sachs-Kochendörfer, or two other relaxed constraint models. The best quantitative agreement is obtained when the critical resolved shear stress (CRSS) ratio for glide on the {112} (111) and {110} (111) slip systems (t₁₁₂/t₁₁₀) is 0.95. A “lath” relaxed constraint model (with ?₂₃ relaxed), associated with the same CRSS ratio, leads to good results for steels with elongated microstructures.     

Production of cold-rolled steel coils

The aspects of cold rolling and subsequent coiling that affect the quality of the steel strip produced are identified on the basis of theoretical and experimental research and production experience at various steel plants. The influence of the strip width and thickness, the surface temperature, the temperature of the rolled metal, and other factors on the stress-strain state of the coils is established. Rational rolling and coiling conditions at continuous and reversible mills are recommended.     

深冲紫铜各向异性及织构相关性分析

通过力学性能检测及电子背散射衍射（EBSD）分析,研究了不同加工工艺生产的厚度为0.5 mm的紫铜带的塑性应变比r、平面各向异性系数Δr与材料深冲性能之间的关系,并对纯铜带材的织构进行了分析。结果表明,塑性应变比r值越大,越不易在厚度方向变形,越适合深冲,且需同时满足Δr要小,才能保证每个面上塑性应变比波动幅度较小。织构分析表明,减小成品加工率可以减少形变织构的体积分数,通过加工率与热处理的配合可以控制形变织构和退火织构的配比,合理的配比可以促进深冲紫铜带后杯口四周的制耳相互抵消,各向异性减小,从而保证了紫铜带冲压后边缘的制耳率。      

Improving the production of cold-rolled steel

The influence of the basic technological factors on the loss of strip width in cold rolling is considered. The influence of technological factors and the state of the working rollers on the formation of light bands (impressions) at each working roller in the first cell of the old-rolling mill is investigated. Means of eliminating these problems in the production of cold-rolled steel are proposed.     

Through-thickness texture gradients in cold-rolled aluminum

The through-thickness texture variations in ∼40 pct cold-rolled polycrystalline aluminum were studied using X-ray diffraction and the electron backscattering pattern (EBSP) technique. The influence of the roll-gap geometry and of sequences of small and intermediate draughts on the development of deformation textures in multipass rolling was considered. It was found that similar textures were formed near the surface and in the central layers of all specimens, while, in the intermediate layers of different plates, different textures were observed. Small draughts gave rise to the shear texture in the intermediate layers, while no pronounced shear texture was revealed anywhere through the thickness of plates rolled with intermediate draughts. It was found that small-draught rolling only has a pronounced effect on the texture if it accounts for a significant strain in the rolling schedule. It was found, furthermore, that nonuniformity of the initial recrystallization texture may be retained in the texture after ∼40 pct rolling.