Some aspects of the role of coal thermoplasticity and coke structure in coal gasification. 2. The effects of pressure and heating rate on dilatometric parameters and optical anisotropy development

An examination of the influence of pressure and heating rate on the thermoplastic properties of a weakly coking coal and of coal with various pitch-like additives was carried out using a high pressure dilatometer. Pressure up to 4 MPa markedly increased the swelling properties and increased the plastic range by decreasing the softening temperature, but the effects of pressure were strongly influenced by rate of heating with high heating rates enhancing the effects. Additions of tar or pitch also enhanced swelling at low pressure. The solid carbonization residues from the dilatometer were examined by polarized light microscopy to determine the content and composition of optically anisotropic species. The anisotropic content was increased by increases in pressure and heating rate and pitch additives enhanced the anisotropic content, especially at low pressure, without affecting the composition of the anisotropy. No direct correlations exist between the dilatometric parameters and the optical anisotropy but their dependence on the conditions emphasizes that when considering high pressure gasification of coal, it is necessary to obtain data under appropriate conditions.     

A two‐scale generalized finite element approach for modeling localized thermoplasticity

Predicting localized, nonlinear, thermoplastic behavior and residual stresses and deformations in structures subjected to intense heating is a prevalent challenge in a range of modern engineering applications. The authors present a generalized finite element method targeted at this class of problems, involving the solution of intrinsically parallelizable local boundary value problems to capture localized, time‐dependent thermo‐elasto‐plastic behavior, which is embedded in the coarse, structural‐scale approximation via enrichment functions. The method accommodates approximation spaces that evolve in between time or load steps while maintaining a fixed global mesh, which avoids the need to map solutions and state variables on changing meshes typical of traditional adaptive approaches. Representative three‐dimensional examples exhibiting localized, transient, nonlinear thermal and thermomechanical effects are presented to demonstrate the advantages of the method with respect to available approaches, especially in terms of its flexibility and potential for realistic future applications in this area. Parallelism of the approach is also discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

P92大规格钢锭锻制管坯穿管断裂致因分析

摘要：某钢厂生产的P92大规格钢锭锻制管坯常出现穿管后产生裂纹的现象,为了探究裂纹产生的原因,在断裂管坯裂纹及附近区域取样,使用金相显微镜与扫描电镜分析裂纹宏观形貌和成分,并进行夹杂物评级与成分分布分析,对无裂纹产品进行高温拉伸试验,考察热制度是否合理。结果表明:穿管断裂样品均存在夹杂物评级超标的问题,未能在精炼过程上浮去除的脱氧产物与卷渣形成的大型夹杂物在穿管过程中引起应力集中,导致裂纹萌生、扩展。针对脱氧产物未被去除的问题,对钙质脱氧剂和铝脱氧剂的加入量进行调整,并延长RH处理结束的弱搅拌时间。针对卷渣带入的夹杂物,对保护渣成分进行优化,选用低熔点保护渣。结果表明这些措施较好地解决了裂纹萌生的问题,产品夹杂物评级合格,大尺寸夹杂物数量大为减少。     

热塑性交联聚乙烯（TPEXa）管材的制备及性能研究

选取耐热聚乙烯（PERT）进行微交联改性制备出一种热塑性交联聚乙烯（TPEXa）管材,使其在保留PERT管热塑性的基础上提高耐热性和抗蠕变性,研究了交联剂含量对TPEXa材料熔体质量流动速率和交联度的影响,并对TPEXa管材的静液压性能、热熔回收性能及回收料的力学性能进行了测试。结果表明,当交联剂的含量为0.08 %时,TPEXa材料的熔体质量流动速率为5.6 g/10 min（190 ℃,21.6 kg）,交联度为2.3 %,负荷变形温度可以达到78 ℃（Tf0.45）,耐温性能较好。制备的管材可以通过95 ℃下22 h、165 h和1 000 h静液压测试,测试所用环应力超过PERT II管接近PEX管材环应力的规定,具有较好的耐温性能和抗蠕变性能,并且可以进行热熔回收,回收料具有较好的力学性能。     

Path-independent integral for the dilatation symmetry group in thermoplasticity

The aim of this study is to establish a fatigue criteria based on an energy threshold corresponding to crack initiation in the case of dilatational symmetry of a structure under thermomechanical loading. An extension of the M integral to thermoplasticity relating to the scaling symmetry is presented. Based on a discrete Lagrangian describing the thermo-inelastic system and Noether's theorem defining the conservation law, the null Lagrangian theorem is applied in order to introduce thermoplasticity. By the use of the divergence theorem, the modified M integral is obtained. Path-domain independence is discussed illustrated by a numerical example.     

聚氨酯弹性体在线缆护套材料中的应用

本文论述了聚氨酯线缆护套材料的配合工艺和优异性能及其影响因素。阐明了这种新型材料是用于特种线缆和光缆护套的理想材料。     

通用气雾型喷胶的研究

以热塑性弹性体为基料,配合增黏树脂、混合溶剂和抛射剂等研制出通用气雾型喷胶。研究了不同类型的热塑性弹性体、增黏树脂、混合溶剂和抛射剂的选择与配比对通用气雾型喷胶性能的影响,并确定了制备通用气雾型喷胶的基本条件,提出了需要深入研究的问题。研究结果表明,当SIS-1209为基料、m(萜烯树脂)∶m(C9石油树脂)=7∶3为混合增黏树脂、m(6号抽提溶剂油)∶m(环己烷)∶m(醋酸乙酯)=3∶2∶1为混合溶剂、抛射剂为二甲醚(DME)以及料气比为1.5∶1时,制取的通用气雾型喷胶性能优异,具有良好的应用前景。     

SUS410S不锈钢边裂原因分析及工艺研究

自不锈钢黑皮卷生产线投产以来,在轧制SUS410S时经常出现热轧边裂缺陷。对SUS410S不锈钢进行高温组织研究,经定量分析确定高温组织与温度的关系。由于高温下存在两相组织,钢的热塑性会降低,导致轧制时容易出现边裂,经研究制定出相应的轧制工艺,以生产出高质量的SUS410S热轧钢带。     

Cu45Zr42.55Y3.45Al9非晶合金的热塑性

采用铜模铸造法制备Cu45Zr42.55Y3.45Al9块体非晶合金,利用三点压弯式粘度仪测定了合金在过冷液区附近的粘度,对合金进行热塑性性能的研究.通过计算得到Cu45Zr42.55Y3.45Al9非晶合金的脆性参数m为31,衡量非晶合金的热塑性加工性能参数m·△T*rx为3.1.在与已报道的有很好可塑性的Cu46Zr42Y5Al7非晶合金比较,可知Cu45Zr42.55Y3.45Al9非晶合金有更好的热塑性性能.此外少量Y元素的添加影响了非晶合金的热塑性.     

双相不锈钢S32101生产工艺研究

从成分控制、热轧和热处理等角度出发,综合研究双相不锈钢S32101的生产工艺并进行优化调整,分析生产试验数据。研究分析表明：在1050～1150℃固溶处理时,组织中铁索体组织与奥氏体组织的比例接近1：1,钢的综合力学性能最佳。