H13钢的退火软化

应用Ｆｆｏｒｍａｓｔｅｒ－Ｄｉｇｉｔａｌ全自动相变仪测定了Ｈ１３钢的退火用ＴＴＴ图，利用物理化学相分析法，扫描电镜分析，Ｘ射线衍射分析，测定研究了Ｈ１３钢不同退火工艺处理后钢的基体中合金元素含量，碳化物类型，尺寸，分布和相对数量，测量钢的退火硬度，分析了硬度与碳化物粒子大小，相对数量，碳化物结构类型的依赖关系。     

钢的退火软化机理

分析了钢的退火软化机理,指出钢的退火软化应从固溶体强化、位错强化、细晶强化等方面降低对铁素体基体的硬化作用,同时使钢呆的出的碳化物球状化、对Ｈ１３钢退火碳化物颗粒的平均直径、弥散度一硬度的 研究表明在碳化物体积分数一定时,硬度是碳化物颗粒平均直径的函数,颗粒直径越大,退火硬度越低     

碳化物对H13钢退火软化的作用

利用电子衍射,分析了Ｈ１３钢退火组织中的碳化物类型,并指出,由于它们溶入奥氏体的强工不同,聚集强度和显微硬度各异,使得碳化物能够长大,并削弱硬度较高的碳化物的硬化作用。     

微量元素对Al—7.5Mg—0.5Mn合金临界退火冷却速度的影响

利用光学显微镜，电化学测试和腐蚀试验等方法系统地研究了微量元素Cr、Zr、Ti和Cu对Al－7．5Mg－0．5Mn合金热轧板材临界退火冷却速度（CRC）及组织性能的影响。结果表明：Cr和Zr能促进退火过程中β相的均匀析出，明显提高CRC和抗剥蚀性（EC），有利于高Mg合金加工工艺的改善；CU虽能促进β相的均匀分布，促进合金的均匀腐蚀，但对冷却速度不敏感；Ti的作用不明显，甚至对抗蚀性有消极影响。     

合金钢的退火不软化行为

某些合金经热处理后产生退火不软化问题。作者对W18Cr4V和18Cr2Ni4WA2种合金钢进行了锻后软化退火试验,对退火组织进行了SEM分析,对合金钢的退火不软化原因进行了探讨,提出钢的退火必须根据等温转变C曲线（即TTT图）,以研究其方法与工艺,从而获得最佳的切削加工性能。实验结果表明：W18Cr4V钢经普通退火处理,硬度偏高（269－286HBS）;采用等温退火方法,软化效果好,满足了切削加工对硬度的一般要求（＜255HBS）;无论采用何种退火方法,18Cr2Ni4WA合金钢的硬度均不能满足要求,只有采用高温回火的办法,方可使其软化。     

冷却速度对 16MnR中板冷弯性能的影响

研究了不同冷却速度对16MnR热轧中板冷弯性能的影响，试验结果表明，理化检验试样冷却速度越快，试样产生热应力越大，冷弯试样开裂的倾向越大；理化检验冷弯试样经石棉保温冷却后的冷弯性能能够真实地反映堆垛成品中板的实际冷弯性能。     

退火工艺对低碳齿轮钢球化退火组织影响

通过对低碳20CrMnTiH齿轮钢在不同保温温度及保温时间进行直接淬火和球化退火试验,分析了退火温度及时间对齿轮钢球化退火组织及硬度的影响。     

冷却速度对等温转变孕育期的影响

应用FTM - 4型Formastor-D全自动相变仪 ,对 35CrMo ,35MnNiCrMo,35CrNi3MoV ,W18Cr4V钢的奥氏体分解孕育期进行了测试研究 ,结果表明 ,冷却速度对孕育期的影响存在一定的规律性 ,即vc 不太大时 ,对孕育期影响较大 ;当vc 增大到一定程度时 ,对孕育期的影响很小     

冷却速度对热轧双相钢相变的影响及双相化的可行性

讨论了随着冷却速度的降低，Ｓｉ－Ｍｎ－Ｃｒ－Ｍｏ系热轧双相钢连续冷却转变的组织中多边形铁素体量增多，贝氏体量减少，且贝氏体由羽毛状向粒状转化，当冷速减小到１．２４－０．２℃／ｓ的范围时，组织中出现针状马氏体。此外，该钢的ＣＣＴ曲线上出现了温度间隔约１８０℃的奥氏体亚稳区，为实现双相化热轧工艺提供了理论依据。     

Effect of annealing cooling rate on microstructure and mechanical property of 100Cr6 steel ring manufactured by cold ring rolling process简

Pre-heat treatment is a vital step before cold ring rolling and it has significant effect on the microstructure and mechanical properties of rolled rings. The 100Cr6 steel rings were subjected to pre-heat treatment and subsequent cold rolling process. Scanning electron microscopy and tensile tests were applied to investigate microstructure characteristic and mechanical property variations of 100Cr6 steel rings undergoing different pre-heat treatings. The results indicate that the average diameter of carbide particles, the tensile strength and hardness increase, while the elongation decreases with the decrease of cooling rate. The cooling rate has minor effect on the yield strength of sample. After cold ring rolling, the ferrite matrix shows a clear direction along the rolling direction. The distribution of cementite is more homogeneous and the cementite particles are finer. Meanwhile, the hardness of the rolled ring is higher than that before rolling.     

Effect of fast cooling rate on the microstructure and mechanical properties of low-carbon high-strength steel annealed in the intercritical region

The effect of fast cooling rate on the microstructure and mechanical properties of low-carbon high-strength steel annealed in the intercritical region was investigated using a Gleeble 1500 thermomechanical simulator and a continuous annealing thermomechanical simulator. The results showed that the microstructure consisted of ferrite and bainite as the main phases with a small amount of retained austenite and martensite islands at cooling rate of 5 and 50 ℃/s, respectively. Fast cooling after continuous annealing affected all constituents of the microstructure. The mechanical properties were improved considerably. Ultimate tensile strength(UTS) increased and total elongation(TEL) decreased with increasing cooling rate in all specimens. The specimen 1 at a cooling rate of 5 ℃/s exhibited the maximum TEL and UTS×TEL(20% and 27 200 MPa%, respectively) because of the competition between weakening by presence of the retained austenite plus the carbon indigence by carbide precipitation, and strengthening by martensitic islands and precipitation. The maximum UTS and YS(1 450 and 951 MPa, respectively) were obtained for specimen 2 at a cooling rate of 50 ℃/s. This is attributed to the effect of dispersion strengthening of fi ner martensite islands and the effect of precipitation strengthening of carbide precipitates.     

含铌微合金钢冷却过程热模拟研究

在Gleeble1500D热模拟机上,利用热膨胀法测定了含铌微合金钢连续冷却转变曲线(CCT曲线),分析了成分对冷却转变的影响,为进一步制定生产工艺提供了依据.     

Effect of cooling rate on the crystallization behavior of perovskite in high titanium-bearing blast furnace slag

The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace（BF） slag was studied using confocal scanning laser microscopy（CSLM）. Results showed that perovskite was the primary phase formed during the cooling of slag. On the slag surface, the growth of perovskite proceeded via the successive production of quasi-particles along straight lines, which further extended in certain directions. The morphology and structure of perovskite was found to vary as a function of cooling rate. At cooling rates of 10 and 30 K/min, the dendritic arms of perovskite crossed obliquely, while they were orthogonal at a cooling rate of 20 K/min and hexagonal at cooling rates of 40 and 50 K/min. These three crystal morphologies thus obtained at different cooling rates respectively corresponded to the orthorhombic, cubic and hexagonal crystal structures of perovskite. The observed change in the structure of perovskite could probably be attributed to the deficiency of O^2-, when Ti2O3 was involved in the formation of perovskite.     

优化填料布置及配水对冷却塔性能的影响

为明确填料布置及配水对冷却塔冷却性能的影响,以浙江国华宁海电厂二期工程6#冷却塔为原型,建立三维数值模型,通过自定义函数加载质量、动量和能量计算程序,与实测对比,模拟结果准确.对比分析3种填料和5种填料布置对超大型冷却塔冷却性能的影响,发现与双向波和双斜波相比,S波冷却效率最优.与S波1.5 m填料等高布置相比,沿径向按无量纲半径rˇ≤0.39(内区)、0.39rˇ≤0.70(中区)和0.70rˇ≤1(外区)非等高1.25-1.5-1.25 m布置的出水温度降低了0.66 K,表明降低填料内区和外区高度,使得空气流速增加,空气流场分布更均匀.另外,当布水总量恒定时,增加冷却水含盐量,3种填料的出水温度均升高2 K左右,说明出水温度升高主要与海水自身性质有关,且受填料波型的影响较小.     

Effect of solution cooling rate on the γ'' precipitation behaviors of a Ni-base P/M superalloy

The effect of cooling rate on the cooling "/' precipitation behaviors was investigated in a Ni-base powder/metallurgy (P/M)superalioy (FGH4096).The empirical equations were established between the cooling rate and the average sizes of secondary and tertiary γ' precipitates within grains and tertiary γ' precipitates at grain boundaries,as well as the apparent width of grain boundaries.The results show that the average sizes of secondary or tertiary γ' precipitates are inversely correlated with the cooling rate.The shape of secondary γ' precipitates within grains changes from butterfly-like to spherical with the increase of cooling rate,but all the tertiary γ' precipitates formed are spherical in shape.It is also found that tertiary γ' may be precipitated in the latter part of the cooling cycle only if the cooling rate is not faster than 4.3℃/s,and the apparent width of grain boundaries decreases linearly with the increase of cooling rate.     

Effect of solution cooling rate on the γ′ precipitation behaviors of a Ni-base P/M superalloy

The effect of cooling rate on the cooling γ′ precipitation behaviors was investigated in a Ni-base powder/metallurgy (P/M) superalloy (FGH4096). The empirical equations were established between the cooling rate and the average sizes of secondary and tertiary γ′ precipitates within grains and tertiary γ′ precipitates at grain boundaries, as well as the apparent width of grain boundaries. The results show that the average sizes of secondary or tertiary γ′ precipitates are inversely correlated with the cooling rate. The shape of secondary γ′ precipitates within grains changes from butterfly-like to spherical with the increase of cooling rate, but all the tertiary γ′ precipitates formed are spherical in shape. It is also found that tertiary γ′ may be precipitated in the latter part of the cooling cycle only if the cooling rate is not faster than 4.3°C/s, and the apparent width of grain boundaries decreases linearly with the increase of cooling rate.     

Effect of cooling rate on the phase transformation and stability of the mushy zone during the solidification of Waspaloy

Scanning electron microscopy(SEM) and energy dispersive X-ray analysis(EDAX) were used to study the microstructure,microsegregation, and fluid flow tendency of the superalloy Waspaloy in the mushy zone,which had been solidified at different cooling rates. The investigation was accompanied with the calculation of Rayleigh numbers.It is found that Ti is the main segregating element and the content of Ti is the highest in the final liquid at the cooling rates of 3-6℃/min.The eta phase(η) precipitate present...