使用三角试块.docx

Resurrecting chill wedges for ductile iron production 对球铁生产进行三角试块测试重新提起重视: often forgotten as a means to measure ductile iron nucleation potential, foundries can turn to chill wedges as a simple tool to ensure melt quality 总是被人遗忘的测量球铁成核潜力的一种方法，铸造厂可以将三角试块测试作为确定熔炼质量的一个简便工具To most iron foundries today, the value of chill wedges in cast iron production is in their ability to provide quick and inexpensive checks of the carbon equivalent in gray iron. Even with the adoption of spectrometers by many foundries for the chemical analysis of iron samples, small to medium-size gray iron foundries still rely on chill wedges for cost-efficient analysis.对于如今的大部分铸造厂来说，确定灰铁的碳含量，冷铁测试是比较快且成本低的一种方式。即使现在很多铸造厂采用光谱仪的方式来对铸铁样件进行化学分析，一些中小灰铁铸造厂仍然以来三角试块测试进行分析，比较经济核算。 By measuring the width of the chill on a solidified wedge sample, foundries can determine the relative carbon equivalent in the cast sample. If necessary, the width of the chill then can be adjusted by adding carbon and/or silicon to the melt to further specify the melt chemistry for the casting to be poured. By correlating the chill width to the section thickness of the casting being poured, a foundry can be assured of pouring carbide free gray iron.根据测量一个三角试块的冷铁宽度，就可以确定相关铸件的碳当量。如果必要，冷铁宽度可以通过加碳和（或）硅的方式来调节，进一步符合所浇铸件的熔炼化学要求。可以将冷铁宽度和所浇铸件界面厚度联系起来，铸造厂就可以确定灰铁中所浇游离碳。Ductile Iran Problems Without Solutions未解决的球铁问题Iron foundries always have been cautioned against repeatedly melting returns without the addition of other materials to the charge such as iron and steel scrap, pig iron, graphite and/ or other ferrosilicon alloys. The resultant cast material from a melt without these additions would have little strength and contain both shrinkage and carbides, even though the chemical composition was still within acceptable range. This result is especially true in the electric melting process. While this phenomenon is not well understood, it is respected.铸造厂里经常反复的熔炼回炉料而不添加其他物质，比如铁，废钢，生铁，石墨以及其他硅铁合金。这是需要提起警戒的做法。这样就会导致没有添加这些物质的铸铁材料抗拉能力和延伸率差，并且会存在缩孔和碳化物，即使化学成分仍在可以接受的范围内。这种结果尤其会出现在电炉融化。虽然这种现象不好理解，但是还是应该被重视。In the production of ductile iron, foundries experience another unexplainable phenomenon termed Monday Morning Iron. This is the term used to describe iron that has been held for too extended a period of time, resulting in a cast material similar to the one described in the previous paragraph. In addition to this, many ductile iron foundries have certain casting jobs that endure shrinkage defects that come and go, even though the chemistry certification remains the same from heat to heat and run to run. While the foundry often chases the iron pouring temperature and blames the iron pourer for these problems, the true reason for the defects never is determined.在球铁生产过程中，另一个不可解释的现象被称为“周一早晨的铁”。这个叫法是用来形容延迟了太长时间的铁，导致和上段所提到的相似问题。除此之外，许多球铁铸造厂里有些产品会时不时的出现缩孔现象，即使化学验证每炉之间，每包之间都是一样的。而铸造厂经常归因于浇铸温度或者责怪浇铸工，但是真正的原因永远没有定论。 When these situations arise, the ductile iron producer can and should resurrect the chill wedge. While the value of the chill wedge for carbon equivalent determination is well-known, its ability to measure the number of nucleation sites available in-cast iron has gone relatively unnoticed. This ability can warn ductile iron foundries against molten base iron that is not up the challenge of producing quality castings.当这些状况出现的时候，球铁生产者应该采用三角试块测试。三角试块测试以确定碳当量为人们所知，但是人们却忽略了它也可以测量铸铁中可用的成核点的数量的能力。这种能力可以使球铁铸造厂避免原铁水产生不良铸件的危险。Chill Wedges for Ductile Iron球铁的块测试Since most ductile iron foundries have the equipment necessary to check metal chemistries, the chill wedge is not needed to check for carbon equivalent. Instead, the chill wedge is needed in ductile iron casting production to check for effective graphite nuclei in the base iron melt.由于现在大部分球铁铸造厂都有必要的设备来确定金属化学成分，所以用铁测试来确定碳当量基本是没有必要的。然而，冷铁测试在球铁生产中用来测试原铁水的有效石墨及晶核是非常必要的。Some foundries believe it isnt critical to check for nucleation potential in the base iron because they use post inoculation, and post inoculations only purpose is nucleation, However, if the base iron does not possess enough nucleation potential, then post inoculation will not have anything to enhance, resulting in low nodule count.一些铸造厂认为鉴定原铁水的形核潜力是没有必要的，因为他们会进行二次孕育，并且二次孕育的唯一目的就是成核。然而，如果原铁水不具备足够的成核潜力，那么二次孕育就不可能有任何提高，导致低球化率。Ductile iron casters can use chills in various ways. They can be used to determine the base line for the length of time molten base metal can be held in the furnace at a given temperature without deterioration. Chill wedges also can be used routinely to insure that the base metal has not been superheated to an excessive temperature.球铁铸造者可以多种方式运用冷铁。可以用来确定铁水在特定的温度下，在铁水不退化的情况下可以保温多久。也可以被用来进行日常检测，确保原铁水不会过度加热。Chill Wedge Specifics三角试块测试特点Chill wedges vary in size according to the width of the back. They may measure 0.25, 0.5, 0.75, 1 and 2 in. at the back, The angle at the sharp edge can vary from 11.5-34.5degrees. The chill wedge dimensions are specified in ASTM A 367.冷铁测试由于底部宽度不同而有不同的大小。底部大小由0.25，0.5，0.75，1，2不等。锐角由11.5-34.5度等。在ASTM A 367中，冷铁尺寸有详细说明。Since carbon equivalent will affect the width of the chill (as measured across the width of the white zone of a broken chill), the size of the chill wedge must be determined by each individual foundry based on their casting mix.由于碳当量影响冷铁宽度（测量的冷铁断面白色区域的宽度），三角试块的大小由每个铸造厂的铸造化学成分决定Low silicon base irons may exhibit an all white chill unless an adequately large wedge test core is used. The width of the chilled iron should be at least 10% of the chill size. If it is less, a larger chill size should be used. If the width is greater that 50% of the chilled width, the chill will be inaccurate and a smaller size should be used. Once the chill size has been established, a baseline can be established.低硅原铁水会呈现完全白色冷铁除非使用恰当的大的三角试块测试。白口铁宽度至少要占到冷铁大小的10%。如果较少的话，应用更大的冷铁。如果白口铁宽度大于50%，激冷就不正确，应用更小的冷铁。一旦冷铁大小确定，那么底线也就确立。During casting of the chill wedge sample, the wedge should be left in the sand core until it is a dull red and then knocked out and allowed to air cool until it is a dull orange and magnetic. It can then be cooled in water.在铸造，冷铁试块样件时，直到三角试样变为暗红色后才能从砂杯里拿出来。然后等到由于空气冷却而变成暗桔色并具磁性后放入水中冷却。Experiences at Farrar在FARRAR公司的经验At Farrar Corp., a 140-employee green sand and no bake ductile iron and austempered ductile iron caster in Norwich, Kansas, the typical chill width for base iron is 0,125 in. using a 0.75 in. chill wedge. This is based on several observations to determine the effect of holding at an elevated temperature and at lower temperatures, as well as experiments with materials such as returns, pig iron and carbon to renucleate the metal.在FARRAR公司有140个铸工，原铁水所用的典型的是，0.75的冷铁，冷铁宽度是0.125。这基于所做的多次观察，确定保持高温和低温的效果。还有对于材料比如回炉料，生铁，以及碳等对金属的再成核作用所做的实验。The samples in Fig. 1 were taken with no changes in temperature and chemistry. It can be seen that as the temperature remains constant, the width of the chill increases as a function of time. Based on this knowledge, if metal is held in the furnace for a period of more than 15-20 mm at 2760F, it must be re-nucleated prior to tapping. If the temperature is lower, the loss of nucleation rate also is lower. At Farrar, metal has been held for 2.5 hr at 2550F and the width of the chill has only increased to 0.132 in.如表一的样品，是在温度和化学没变化的情况下所测结果。可以看出，当温度持续保持在一定的值，冷铁宽度随着时间的推迟而上升。基于此，如果金属在2760F（大概1516摄氏度）下持续15-20分钟，在被倒出之前一定会被再成核。 In Fig. 2, metal was held for more than two hr at an elevated temperature while graphite was used to maintain the carbon level. As shown by samples C, D and E, the graphite helped to reduce the chill. However, the results are erratic and a small addition of pig iron or returns would help maintain good nucleation.如表二，金属被保持在高温 超过2小时，同时用石墨来维持碳含量。如样品C、D、E所示，石墨有助于减少冷铁。然而，结果很不稳定，加少量的生铁和回炉就有助于保持良好的成核。Farrar also has experimented with changes in charge make up and taken chill samples to determine if any affect in the chill wedge was evident. The charge make up was altered through a range of 14-21% pig iron, 25-38% scrap steel and 48-56% returns. The result: no affect in the depth of the chill was detected by changing any of the charge ratios.FARRAR也同样也在上料配比做了实验，并取冷铁样品来确定在三角试样上所发生的较明显的效果。上料配比范围变化如下，生铁为14%-21%，废钢25%-38%，回炉48%-56%。结果是：上料配比变化对冷铁深度未发现任何明显影响。Farrar also has used both pig iron and its own returns to bring back nucleation sites. Either option produces about the same results, as 0.71% of the metal is sufficient when reintroduced to the melt to bring back nucleation.FARRAR同样也使用生铁和它自己的回炉来恢复成核点。无论是哪种选择都是同一种结果，因为当重新引入熔炼并恢复成核，铁水的0.71%是足够的。Time and temperature are the enemies of nucleation sites in ductile iron. Chill wedges can be an important tool to determine how much time and at what temperature metal can be held without losing the nucleation potential. Once the time line is established, then a procedure can be established to ensure that if the time is exceeded, a re-nucleation process for the metal will follow.时间和温度对于球铁来说是成核的敌人。三角试块是非常重要的一个工具确定在多长时间，多高的温度线可以保持成核潜力的小事。一旦确立了一个时间界限，那么程序就能确定保证如果超过一定的时间，那么金属再成核就要跟上。Fig. 1表一These chill wedge samples show that as the melt temperature remainsc