共查询到19条相似文献,搜索用时 78 毫秒
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缸筒与耳轴的焊接式连接有诸多优点,但也避不开常见的焊接变形问题.文章根据企业自身的生产环境,探索粗镗缸筒与耳轴的配合间隙对缸筒内孔焊后变形的工艺研究方法及影响,从中找出其焊接变形的规律,为油缸设计、粗镗缸筒的备料和生产工艺提供依据. 相似文献
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为了稳定亚温淬火工艺与工业化生产,通过力学性能分析及显微组织观察,对比了正火+亚温淬火+回火、在线淬火+亚温淬火+回火、离线淬火+亚温淬火+回火3种热处理工艺对690 MPa级海洋工程用钢板组织性能的影响。结果表明,采用离线淬火+亚温淬火+回火工艺结果最理想,能够大幅度提高钢板的低温冲击性能和伸长率。同时,还能够获得较低的屈强比,断口形貌全部为韧窝,呈明显的韧性断裂,而且随着亚温保温时间的增加,强度逐渐提高,当保温时间达到30 min以后,强度及条片状铁素体基本不发生变化;采用直接淬火态+亚温淬火+回火虽然可以保证高强度低屈强比,但是冲击功表现较为离散,稳定性欠佳,断口形貌为混合型,以韧性断裂为主;采用正火态+亚温淬火+回火工艺效果最差,尤其是不能保证钢板低温韧性,断口形貌全部为解理,呈明显的脆性断裂,其中片条状铁素体形貌是决定优良低温冲击性能的关键因素。 相似文献
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利用金相显微镜、洛氏硬度计和扫描电镜,对经过预备热处理(退火、淬火、调质)+亚温淬火+高温回火处理(又称临界区淬火+回火)后的42CrMo钢的组织、冲击性能以及断口形貌进行了观察和分析。结果表明,预备热处理为退火处理时,亚温处理后残留的铁素体粗大不均;且在回火索氏体之间分布不均匀;预备热处理为淬火处理和调质处理时,残留的铁素体形态细小,且与回火索氏体均匀分布。采用不同预备热处理时,亚温处理后的硬度差别很小。亚温处理后42CrMo钢的冲击性能均高于常规调质处理后的冲击性能;预备热处理为调质处理时,亚温处理后的冲击功最大,从其断口形貌中可以看出,其起裂区和裂纹纤维扩展区所占比例较退火处理和淬火处理时要大。因此,调质处理更适合作为42CrMo钢的预备处理。 相似文献
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1双缸加载回路基本原理为了对油缸进行性能试验,需用加载回路通过加载缸对被试缸进行加载。这种采用一台油缸对另一台油缸用机械联接进行加载的试验方法,要求油缸台架具有足够的强度和刚度,要占用很大的空间,试验装置的加工制造费用很高,一般非专业试验室不具备这种... 相似文献
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基于经典晶体塑性理论,建立了耦合孪生的晶体塑性本构模型并进行了全隐式积分的数值实现.该本构模型采用饱和硬化法则,并采用孪生阻力与滑移硬化之间的正比关系来描述孪生对滑移硬化影响及孪生硬化行为.针对该本构模型的13个参数,结合各参数物理意义提出了参数的分类确定方法.以孪生诱导塑性(TWIP)钢Fe-22Mn-0.6C为例,着重对硬化参数的局部灵敏度进行了分析,研究了各硬化参数对宏观力学响应、孪生激活和演化的影响,根据变形机制的不同宏观变形过程可区分为孪生硬化阶段和孪生硬化失效阶段,进而给出了硬化参数确定的步骤及其建议取值范围.结果表明:初始滑移阻力与屈服极限线性相关,取值范围在80~160 MPa之间;孪生硬化指数增大使得孪生硬化阶段减弱,其取值范围应在0~3之间;孪生阻力与滑移阻力比值增大,则孪生增长率降低,硬化率拐点后移,直至拐点消失,其取值范围在1~1.3之间. 相似文献
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摘要:为了研究大变形管线钢应变硬化行为及其表征参数之间关联性,采用TMCP工艺调控制备了9种不同贝氏体体积分数的铁素体/贝氏体(F/B)多相组织钢。通过力学性能及应变硬化行为分析,对应变硬化指数、应力比、屈强比和伸长率等大变形管线钢应变硬化能力表征参数之间的关联性及其机制、内涵和适用范围进行了研究。结果表明,F/B多相钢中,应力比Rt20/Rt10和均匀伸长率与应变硬化指数呈线性正比关系,屈强比与应变硬化指数呈非线性反比关系,应力比Rt50/Rt10在一定条件下与应变硬化指数存在线性关系,应力比Rt15/Rt05、总伸长率、应变硬化指数之间不具备明显的关系。通过应变硬化行为分析合理阐释了以上参数之间的关联机制,并阐释了其内涵和适用范围。硬化指数、均匀伸长率和应力比Rt20/Rt10应作为描述F/B多相钢塑性形变阶段应变硬化能力的主要参数,屈强比和应力比Rt50/Rt10则应作为次要参数。采用工业化生产数据对上述结论进行了验证,与所得结论吻合良好。 相似文献
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S. A. Firstov T. G. Rogul’ N. A. Krapivka S. S. Ponomarev V. N. Tkach V. V. Kovylyaev V. F. Gorban’ M. V. Karpets 《Russian Metallurgy (Metally)》2014,2014(4):285-292
The nature of solid-solution hardening of high-entropy alloys is discussed using an equiatomic bcc AlTiVCrNbMo alloy as an example. The hardening of the alloy is found to be characterized by an increase in the temperature dependence of the component of the critical shear strength and by anomalously high athermic hardening due to the perpendicular slip plane of the Burgers vector component. A relatively simple expression is proposed to estimate the detected hardening ΔH(Δσ). 相似文献
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N. A. Koneva E. V. Kozlov L. I. Trishkina A. N. Zhdanov 《Russian Metallurgy (Metally)》2010,(4):264-267
Strain hardening of nanograined polycrystals is studied using copper-based alloys as an example. The stages of strain hardening
are compared for these alloys and for pure metals (copper, gold) having a similar grain size in the range 40–200 nm. The stress
σ-strain ɛ dependence demonstrates that the strain hardening of these polycrystalline nanograined materials proceeds, as a
rule, in three stages with different hardening mechanisms. 相似文献
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Weilong Hu 《国际钢铁研究》2000,71(6-7):261-263
A new exponential hardening rule is brought forward to apply for planar anisotropy strain‐hardening sheet metals. Three exponential hardening relations measured along the rolling direction, 45°‐angle and 90°‐angle direction against rolling direction are just the special cases of this model. Based on this model to solve some plastic deformation problems for anisotropic strain‐hardening materials, some functions and calculating results, such as constitutive relations, forming limit characteristic, springback and other parameters associated with these types of materials, should be more likely to approach real states. So this anisotropic strain‐hardening model is very important for applying sheet metal forming simulation. 相似文献
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V. M. Blinov O. P. Tchernogorova E. I. Drozdova I. A. Afanas’ev 《Russian Metallurgy (Metally)》2006,(2):161-171
The structure and hardening of austenitic steels subjected to shock-wave treatment have been studied. This treatment is shown to form a structure whose cell size decreases with increasing pressure. The treatment-induced hardening of the steels can be estimated using the Hall-Petch relation. At the same degrees of residual deformation, shock-wave treatment results in a significantly higher degree of hardening of the austenitic steels as compared to cold rolling. The degree of hardening increases with decreasing stacking-fault energy in austenite. 相似文献
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Plasma surface hardening process was performed to improve the performance of the AISI 1045 carbon steel. Experiments were carried out to characterize the hardening qualities. A predicting and optimizing model using genetic algorithm-back propagation neural network (GA-BP) was developed based on the experimental results. The non-linear relationship between properties of hardening layers and process parameters was established. The results show that the GA-BP predicting model is reliable since prediction results are in rather good agreement with measured results. The optimal properties of the hardened layer were deduced from GA. And through multi optimizations, the optimum comprehensive performances of the hardened layer were as follows: plasma arc current is 90 A, hardening speed is 22 m/min, plasma gas flow rate is 60 L/min and hardening distance is 43 mm. It concludes that GA-BP mode developed in this study provides a promising method for plasma hardening parameters prediction and optimization. 相似文献