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904L是一种高铬镍钼含量的超级奥氏体不锈钢,相比316L和317L它具有更好的耐腐蚀性能,本文分析7904L的焊接特点,并通过焊接工艺评定试验保证了产品的机械性能,确定了合理的焊接工艺并成功应用于实践,焊接质量得到了保证。 相似文献
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以铸态904L超级奥氏体不锈钢热压缩实验数据为样本,采用BP人工神经网络建立了以变形温度、应变速率和应变量为输入层,流变应力为输出层的热变形本构模型。结果表明,BP网络预报的流变应力值与实验值比较吻合,平均绝对误差值为2.06%。该模型能够准确反映铸态904L超级奥氏体不锈钢的高温流变行为,为合理控制热轧工艺参数提供一定参考。 相似文献
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采用MMS-200热模拟试验机对904L超级奥氏体不锈钢进行了单道次热压缩实验.研究了变形工艺参数对流变应力的影响,建立了热加工图并揭示了动态再结晶行为的不均匀性.结果表明,由于摩擦的存在,变形后试样出现了明显的"鼓肚"现象,造成试样内部应变的不均匀性;微观组织表征发现即使材料的应力-应变曲线表现出典型的动态再结晶行为... 相似文献
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为优化后续轧制工艺,利用Gleeble-3800热力模拟机,对轧制态254SMo超级奥氏体不锈钢进行等温恒应变速率压缩试验,研究了254SMo超级奥氏体不锈钢在变形温度为900~1100℃,应变速率为0.005~5 s-1的热变形行为及微观组织演变。结果表明,随着变形温度升高及应变速率降低,峰值应力减小,且流变曲线的单峰特征变得明显,说明高温低应变速率下254SMo容易发生动态再结晶;三种形式的Arrhenius本构方程预测精度对比显示,指数形式的精度最高,相关系数达97.496%,变形激活能为546 kJ/mol。 相似文献
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在超级奥氏体不锈钢CK3MCuN的制造过程中,为使其具有单相奥氏体组织,在固溶处理及焊接中采取有效的措施,抑制奥氏体之外的金属间化合物的产生,如高温σ相、碳化物等,有利于表现出CK3MCuN良好的耐蚀性。对固溶处理、焊接后的微观组织进行了分析,结果表明,CK3MCuN铸钢件通过合理、严格的热加工工艺可以有效抑制奥氏体之外的金属间化合物的产生,且点腐蚀性能良好,可以满足客户要求。在工程应用中可以安全、有效地使用CK3MCuN材质的零部件及设备。创新点: 根据CK3MCuN铸钢件的热处理及焊缝的试验与分析,给出了较为合理实用的制造工艺,可供CK3MCuN的制造者及使用者借鉴。 相似文献
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Shing-Hoa Wang Chia-Chang Wu Chih-Yuan Chen Jer-Ren Yang Po-Kay Chiu Jason Fang 《Metals and Materials International》2007,13(4):275-283
A fatigue behavior analysis was performed on superaustenitic stainless steel UNS S31254 (Avesta Sheffield 254 SMO), which
contains about 6wt.% molybdenum, to examine the cyclic hardening/softening trend, hysteresis loops, the degree of hardening,
and fatigue life during cyclic straining in the total strain amplitude range from 0.2 to 1.5%. Independent of strain rate,
hardening occurs first, followed by softening. The degree of hardening is dependent on the magnitude of strain amplitude.
The cyclic stress-strain curve shows material softening. The lower slope of the degree of hardening versus the strain amplitude
curve at a high strain rate is attributed to the fast development of dislocation structures and quick saturation. The ε martensite
formation, either in band or sheath form, depending on the strain rate, leads to secondary hardening at the high strain amplitude
of 1.5%. 相似文献
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The effect of aging in air at 650°C for 100~1000 h on the tensile properties of superaustenitic stainless steel in the range
RT-750°C and the fatigue crack growth behaviour at RT and 650°C was studied. Yield strength and ultimate tensile strength
were almost the same between the as-received and the aged specimen. The fracture strain, however, decreased significantly
from aging, and the fracture surface of the aged specimen at RT test was intergranular. The fatigue crack growth rate at RT
is enhanced by aging at the high stress intensity factor range. This is due to the occurrence of an intergranular fracture
in the aged specimen. At 650°C the fatigue crack growth behaviour of both the as-received and the aged specimen was almost
same with no intergranular fracture. 相似文献
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The first generation of superaustenitic 6Mo steels like 254 SMO® has been further developed into a new steel–654 SMO®–containing very high amounts of those alloying elements most beneficial for the resistance to localized corrosion. 654 SMO is compared with other stainless steels and nickel-base alloys in tests performed in various kinds of seawater. The new steel is much superior to the 6Mo steel under all conditions investigated and compares favourably with Alloy C–276 in most tests. The most corrosive condition among those investigated represents a seawater system where aerobic and anaerobic areas exist simultaneously. 相似文献
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Solidification cracking susceptibilities of two types of superaustenitic stainless steel, 254SMO and SR50A, were evaluated by transverse Varestraint tests. The susceptibilities were compared with those of conventional austenitic stainless steel 316L, and factors influencing the difference of susceptibility were discussed. The comparison showed that 254SMO and SR50A are more sensitive to solidification cracking than 316L. In the transverse Varestraint tests, both total and maximum crack lengths are longer in the superaustenitic stainless steel. Because of the longer maximum crack length, the superaustenitic stainless steel also has a wider brittleness temperature range of cracking than 316L: about 178 °C for the superaustenitic stainless steel and 43 °C for 316L. It is believed that straight subgrain boundaries owing to the cellular dendritic solidification and segregations of sulfur and phosphorus in the subgrain boundaries of superaustenitic stainless steel make it more sensitive to solidification cracking. In addition to the solidification cracking, reheat cracking is also observed within the previous weld bead in the superaustenitic stainless steel because of fully austenitic solidification with significant segregations. This suggests that caution should be given to the occurrence of reheat cracking when superaustenitic stainless steel is multi pass welded. 相似文献
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为研究一种制动杠杆螺栓用不锈钢材料的热变形行为及锻造工艺,利用热模拟试验机对材料进行了高温压缩试验,得到了该材料的真应力-真应变曲线和显微组织。将高温压缩试验得到的数据导入有限元模拟软件Deform-3D中,对制动杠杆螺栓的成形过程进行了数值模拟,分析了成形过程中的载荷-行程曲线、等效应力场分布等,最后根据优化得到的工艺参数设计了相应模具,并做了工艺试验,工艺试验得到的制动杠杆螺栓锻件充填饱满、尺寸符合要求、锻造流线分布合理,且锻件经过机加工后,没有发现锻造缺陷,符合使用要求。该研究对此类零件的生产具有一定的指导意义。 相似文献
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Shing-Hoa Wang Chih-Sheng Huang Woei-Shyan Lee Tao-Hsing Chen Chia-Chang Wu Charles Lien Hung-Yin Tsai 《Metals and Materials International》2009,15(6):1007-1015
A considerable volume of γ phase increases in the fusion zone (weld metal) for two duplex stainless steels after a high-strain-rate
impact. The strain-induced γ phase formation in the fusion zone results in local hardness variation depending on the strain
rate. The α phase content in the fusion zone decreases as the impact strain rate increases for SAF 2205 DSS and SAF 2507 DSS.
The results of the two-phase content measured by Ferritoscope correspond to that assessed by image analyses. In contrast,
superaustenite stainless steel is unaffected by such an impact owing to its fully stable austenization. Impacted welds at
a high strain rate of 5 × 103 s−1 reveal feather-like surface creases along the solidified curved columnar grain boundaries. The apparent surface creases are
formed due to the presence of diffuse Lüders bands, which are caused by heavy plastic deformation in coarse-grain materials. 相似文献