珠光体

It has been found that, the matrix hardnesses is reduced by about 30 % with the increase of parameter P, and there exists a hardness gradient in phase α from grain center to grain boundary, which is in correspondence with the concentration gradient of alloy elements.

多年来的研究业已发现珠光体耐热钢在高温下长期运行中会发生珠光体球化、碳化物聚集、合金元素在固溶体和碳化物之间重新分配等组织变化[1]。

Strain fatigue life in pearlite is longer than that in tempered sorbite with same tensile strength, which can be attributed to the small plastic strains in pearlite.

轨钢的应变疲劳是塑性应变控制过程，抗拉强度相等时，珠光体的应变疲劳寿命高于回火索氏体的疲劳寿命，其原因在于珠光体具有较小的塑性应变幅。

It was found in this investigation that boron exerted considerable influenceon the nucleation and growth of pearlite. In a hypoeutectoid steel, boron delayedthe starting time of pearlite formation at the maximum pearlite formation temp-erature. Boron did not effect the relation of nucleation rate with time butonly increased the incubation period for pearlite nucleation.

从实验结果证明，硼对珠光体的成核及成长是有影响的；在亚共析钢中硼促使珠光体的开始形成时间推迟，增长了珠光体成核的孕育期，但对成核率与时间的关系，在近于A_1温度(700℃)时，略为加速，而在珠光体转变速度最大的温度(650℃)时却没有影响。

With the addition of Al of about 1 wt%, the proeutectoid cementites were restrained during equilibrium transformation and dynamic phase transformation, the stability of undercooled austenite during deformation was increased, retarding the formation of pearlite and the interlamellar spacing of pearlite was decreased.

Al的加入使动态相变过程中奥氏体的稳定性提高、珠光体转变推迟，进一步细化了珠光体片层间距。

A pearlitic steel is composed of numerous pearlitic colonies with random orientations, and each colony consists of many parallel lamellas of ferrite and cementite.

珠光体钢由众多随机取向的珠光体团构成，每一珠光体团又包含了许多平行的铁素体和渗碳体片层。

According to the morphological characteristics of cementite lamellae, the deformed pearlite can be divided into three kinds: irregularly bent lamella (pearlite lamella originally inclined with large angles to the rolling plane and irregularly bent after deformation); coarse lamellae with shear-band (the rhomboidal blocks of weakly deformed lamella bounded by shear band) and fine l...

按 渗碳体形态特点，变形珠光体组织可分为以下3种类型：(1)不规则弯曲片层型，即变形后的渗碳体与轧制面呈大角度偏离且不规则弯曲的珠光体。(2)带有剪切带的粗大片层型，即被渗碳体剪切带分开且变形轻微的珠光体。(3)精细片层型，即与轧制方向平行排列、片间距细小且渗碳体严重变形的珠光体。精细片层区域的比例随着轧制压下率的提高而增大。此外，重度冷轧变形还引起渗碳体严重塑性变形和部分溶解。

According to the morphological characteristics of cementite lamellae, the deformed pearlite can be divided into three kinds: irregularly bent lamella (pearlite lamella originally inclined with large angles to the rolling plane and irregularly bent after deformation); coarse lamellae with shear-band (the rhomboidal blocks of weakly deformed lamella bounded by shear band) and fine lamella (heavily deformed lamella aligned parallel to the rolling direction with fine interlamellar spacing).

按渗碳体形态特点，变形珠光体组织可分为以下3种类型：(1)不规则弯曲片层型，即变形后的渗碳体与轧制面呈大角度偏离且不规则弯曲的珠光体。(2)带有剪切带的粗大片层型，即被渗碳体剪切带分开且变形轻微的珠光体。(3)精细片层型，即与轧制方向平行排列、片间距细小且渗碳体严重变形的珠光体。

It is found that before the pearlitic and upper-bainitic reactions, a pro-cutectoid orpro-bainitic phase is precipitated along the austenite grain boundaries in the cyanidedsamples; and it is thought that this is likely a nitrogen-bearing phase which provides thephase boundary effect for the nucleation of the reactions and impoverishes the parentaustenite in alloy content, thus accelerating the transformation of austenite.

实验中发现，在珠光体及上贝茵体形成之前，氰化试样中均有一种过剩相沿奥氏体晶粒边界析出。这种先析相可能是一种含氮的化合物，其析出为珠光体及上贝茵体的非自发形核提供了现成的有利界面，并使奥氏体合金化程度降低，因而加速了转变。

The results show that BS 460MPa grade reinforced bar can be produced all from Q235 or 20MnSi billet by the remained heat treatment process but the production cost of the former is lower. When the water pressure minishes, the intensities of reinforced bar reduce; the higher the temperature at the entrance of cooling bed is, the lower the intensities are. Therefore, the commendatory process parameters are that five stages coolers should be opened, water pressure should be all 1.8～2.0MPa and the temperature at the entrance of cooling bed of Q235 reinforced bar should lower than 650℃. The typical microstructure(Q235): the surface layer is tempered sorbite; the transition layer is pearlite and ferrite, and the partial ferrite is acicular; the core is pearlite and ferrite and the grain fineness is 8～10 grade. The yield strength is reduced by 10～20MPa after natural ageing and it can be simulated by artificial ageing(100℃×2h or 200℃×1h).

结果表明，Q235和20MnSi钢都可以利用余热处理工艺生产出性能合格的钢筋，但前者的生产成本较低；水压减小，钢筋强度降低，上冷床温度越高，强度越低，推荐5段水冷器全开，水压均为1.8～2.0MPa，Q235钢筋的上冷床温度应控制在650℃以下；钢筋典型的金相组织（Q235）表层为回火索氏体，过渡层为珠光体+铁素体且部分铁素体呈针状，心部为珠光体+铁素体，晶粒度8～10级；自然时效后屈服强度下降10～20MPa，用人工时效可以模拟自然时效，工艺是100℃×2h或200℃×1h。

The chemical composition,microstructure,mechanical properties,production system and economic benefit of as cast ferrite/perlite spheroidal graphite cast iron miner's truck wheel are introduced.

介绍了铸态铁素体－珠光体球墨铸铁矿车轮的化学成分、组织性能、生产工艺及经济效益。使用结果表明，铸态铁素体－珠光体球墨铸铁矿车轮的使用寿命约是ZG35矿车轮的1.5倍

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。