浅论氯离子渗透试验方法

本文对目前最常用的三种混凝土氯离子渗透试验方法ASTMC1202、NEL法和RCM法进行讨论,并分析了各自的优缺点。     

常压下石油馏分蒸馏曲线换算的数学模型

对常压下石油馏分的实沸点蒸馏曲线与平衡汽化曲线以及恩氏蒸馏曲线与平衡汽化曲线的换算图表进行了回归,同时总结了文献中已有的常压下各蒸馏曲线的换算模型,从而建立了一套完整的常压蒸馏曲线换算模型,该模型可用于双向计算。误差分析表明该模型具有可靠的计算精度。选取实测数据对该模型进行验证,结果表明新模型的计算值与实测数据吻合较好,计算准确性优于文献模型。     

电站阀门用ASTM材料压力，温度等级的应用与分析

介绍了电站阀门用ASTM材料的压力温度等级的计算方法及常用高温高压电站阀门压力温度等级与磅级制阀门的关系     

Comparison of methods to determine CTOD for SENB specimens in different strain hardening steels

Methods for determining crack tip opening displacement (CTOD) given in national and international standards are compared for steels with a range of strain hardening characteristics. Crack tip opening displacement measurements were made from single‐edge notched bend notches using a silicone rubber casting method. The finite element model produced good agreements with predictions of these CTOD measurements. The versatility of the finite element model enabled CTOD from the original crack tip and the 45° intercept method to be compared. The 45° CTOD generally underestimates the original crack tip CTOD, and is less useful for conditions with stable crack extension. Apart from the high strain hardening material, CTOD calculated using BS 7448‐1, WES 1108 (JWES), and ASTM E1820 was slightly lower than the values determined from silicone measurements and modelling, which is conservative. ASTM E1820 gave the largest underestimation of CTOD, whilst BS 7448‐1 may be unsuitable for higher strain hardening steels, where the standard predicts higher CTOD than measured from the replica. JWES gives the most consistent estimation of CTOD for steels with a wide range of strain hardening values.     

催化裂化分馏和吸收稳定全流程模拟与优化

应用Aspen-Plus流程模拟软件,对金陵石化Ⅰ催化裂化分馏和吸收稳定系统进行全流程模拟,产品的恩氏蒸馏曲线基本与实际相符。分析得出,随着分馏塔顶循、一中返塔温度的上升,汽油干点和柴油的95%馏出温度均上升,此外,在保证稳定塔塔底再沸器热负荷和分馏塔产品质量合格的前提下,模拟求得一中最小循环量和相应的油浆占总取热量的最大比例;其次,随着补充吸收剂流量的增大,干气中C_3~+的体积分数逐渐降低,解吸塔和稳定塔再沸器的热负荷逐渐增大;随着解吸塔再沸器热负荷的增加,液态烃中C_2体积分数逐渐下降,稳定塔再沸器的热负荷也随之增大。由此可知,为了保证产品质量,需调节分馏塔各相应段的取热量,并调节好吸收稳定系统的再沸器热负荷、液气比等操作参数。整个模拟与优化过程对生产具有积极的指导意义。     

Laboratory evaluation of anti‐fretting lubricants

To characterise the friction and wear behaviour of materials and lubricants under a variety of operating conditions, laboratory models are frequently used to provide useful information. For example, during the development and/or selection of tribomaterials and lubricants, laboratory ranking of candidate products can save many hours of field testing. A reciprocating ball‐on‐flat wear test rig has been developed to rank the performance of materials, surface coatings, and lubricants under boundary, extreme‐pressure, or fretting conditions in a variety of environments and at various temperatures. The rig design is based on ASTM G133–1995. The friction force and wear are measured on both specimens while the load, stroke length and frequency, test temperature, lubricant type, test duration, surface topography of both ball and flat specimens, specimen materials, and environmental conditions are noted. The results presented in this paper refer specifically to a series of tests performed to evaluate various anti‐fretting lubricants. Two lubricants are compared in terms of friction coefficient and wear volume over time. A clear difference is shown between the two products.     

ASTM A487B铸造曲轴材料评定的工艺改进

我们从原材料选用和热处理方案两方面阐述了材质为ASTM A487B的铸造曲轴材料评定试块的生产工艺。结论是:采用精炼+真空除气冶炼工艺、两次正火+调质的性能热处理工艺能够达到用户的技术要求。     

50 t EAF-LF(VD)-CC流程开发4130钢Φ350 mm连铸圆坯的生产实践

采用50 t EAF-LF(VD)-CC-缓冷工艺,通过控制电弧炉终点[C]0.12%~0.25%,终点[P]≤0.015%,出钢预脱氧和合金化,LF精炼时采用CaO-Al₂O₃系无氟预熔精炼渣,以及连铸综合铸坯控制技术包括钢水深度≥800 mm 19 t中间包,控制拉速0.35~0.45 m/min,钢水过热度15~25℃,优化二冷制度和末端电磁搅拌参数(350 A/8 Hz)等工艺措施,所生产的4130钢(/%:0.29~0.31C、0.25~0.28Si、0.51~0.54Mn、0.96~0.98Cr、0.19~0.20Mo、0.016~0.025A1)Φ350 mm连铸圆坯的[O]、[N]分别为(12~14)×10^-6、(55~70)×10^-6,低倍组织≤1.0级,锻件的非金属夹杂物A、B≤1.0级、C、D≤0.5级,锻件超声波探伤级别、尺寸公差及表面质量等质量指标均满足用户要求。     

Intensification of continues biodiesel production process using a simultaneous mixer- separator reactor

Nowadays, Biodiesel as an alternative, sustainable and less toxic fuel has been accepted by both researchers and industry. Developing process intensification reactors with the aim of reaching more efficient process has captured the attention of many researchers recently. In order to examine a novel reactor for biodiesel production using Waste Cooking Oil as a cost-effective feedstock, and KOH as an efficient homogeneous catalyst, the present study was developed to investigate three effective parameters (Oil flow rate, catalyst concentration and reaction temperature) focusing on transesterification reaction yield in the Simultaneous Mixer-Separator (SMS) reactor, designed and fabricated exclusively for biodiesel production at Tarbiat Modares University (TMU). As the findings indicated, rising the flow rate presented an increasing trend up to 15 mL/min and a decreasing trend was found after this level. Also, catalyst concentration up to 1% w/w showed an increasing trend which was significant. Analysis of reaction temperature showed that at 60^°C the maximum yield is obtained. Furthermore, 15 mL/min oil flow rate, 1% w/w KOH concentration and 60^?C were selected as the optimal reaction conditions for continuous biodiesel production. At this point, the produced biodiesel followed by the purification step reached the yield of 96%. The produced biodiesel physicochemical properties were found to meet ASTM D6751 standard. All in all, continuous production capability, higher productivity, simultaneous separation of products, and the successful handling of waste resources distinguish the SMS reactor as a potential and efficient process intensification reactor.     

热煨弯管拉伸试样尺寸的选择

拉伸试样的尺寸对拉伸试验结果的影响较大,为了提高热煨弯管拉伸试验结果的准确率,降低试验成本,结合常用热煨弯管的取样位置及GB/T 228.1和ASTM A370标准对管材拉伸试样尺寸的要求,对两种标准下不同试样尺寸进行的拉伸试验结果进行了对比分析。结果表明,热煨弯管拉伸试样尺寸采用ASTM A370要求的标距为50 mm的试样更加实用;拉伸试验时,应依据热煨弯管的不同直径,按照相应标准选用尺寸不同的试样,以提高试验结果的准确性。