使用三角試塊.docx

Resurrecting chill wedges for ductile iron production 對球鐵生產(chǎn)進行三角試塊測試重新提起重視: 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 總是被人遺忘的測量球鐵成核潛力的一種方法，鑄造廠可以將三角試塊測試作為確定熔煉質(zhì)量的一個簡便工具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.對于如今的大部分鑄造廠來說，確定灰鐵的碳含量，冷鐵測試是比較快且成本低的一種方式。即使現(xiàn)在很多鑄造廠采用光譜儀的方式來對鑄鐵樣件進行化學(xué)分析，一些中小灰鐵鑄造廠仍然以來三角試塊測試進行分析，比較經(jīng)濟核算。 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.根據(jù)測量一個三角試塊的冷鐵寬度，就可以確定相關(guān)鑄件的碳當(dāng)量。如果必要，冷鐵寬度可以通過加碳和（或）硅的方式來調(diào)節(jié)，進一步符合所澆鑄件的熔煉化學(xué)要求?？梢詫⒗滂F寬度和所澆鑄件界面厚度聯(lián)系起來，鑄造廠就可以確定灰鐵中所澆游離碳。Ductile Iran Problems Without Solutions未解決的球鐵問題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.鑄造廠里經(jīng)常反復(fù)的熔煉回爐料而不添加其他物質(zhì)，比如鐵，廢鋼，生鐵，石墨以及其他硅鐵合金。這是需要提起警戒的做法。這樣就會導(dǎo)致沒有添加這些物質(zhì)的鑄鐵材料抗拉能力和延伸率差，并且會存在縮孔和碳化物，即使化學(xué)成分仍在可以接受的范圍內(nèi)。這種結(jié)果尤其會出現(xiàn)在電爐融化。雖然這種現(xiàn)象不好理解，但是還是應(yīng)該被重視。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.在球鐵生產(chǎn)過程中，另一個不可解釋的現(xiàn)象被稱為“周一早晨的鐵”。這個叫法是用來形容延遲了太長時間的鐵，導(dǎo)致和上段所提到的相似問題。除此之外，許多球鐵鑄造廠里有些產(chǎn)品會時不時的出現(xiàn)縮孔現(xiàn)象，即使化學(xué)驗證每爐之間，每包之間都是一樣的。而鑄造廠經(jīng)常歸因于澆鑄溫度或者責(zé)怪澆鑄工，但是真正的原因永遠沒有定論。 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.當(dāng)這些狀況出現(xiàn)的時候，球鐵生產(chǎn)者應(yīng)該采用三角試塊測試。三角試塊測試以確定碳當(dāng)量為人們所知，但是人們卻忽略了它也可以測量鑄鐵中可用的成核點的數(shù)量的能力。這種能力可以使球鐵鑄造廠避免原鐵水產(chǎn)生不良鑄件的危險。Chill Wedges for Ductile Iron球鐵的塊測試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.由于現(xiàn)在大部分球鐵鑄造廠都有必要的設(shè)備來確定金屬化學(xué)成分，所以用鐵測試來確定碳當(dāng)量基本是沒有必要的。然而，冷鐵測試在球鐵生產(chǎn)中用來測試原鐵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.一些鑄造廠認為鑒定原鐵水的形核潛力是沒有必要的，因為他們會進行二次孕育，并且二次孕育的唯一目的就是成核。然而，如果原鐵水不具備足夠的成核潛力，那么二次孕育就不可能有任何提高，導(dǎo)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.球鐵鑄造者可以多種方式運用冷鐵?？梢杂脕泶_定鐵水在特定的溫度下，在鐵水不退化的情況下可以保溫多久。也可以被用來進行日常檢測，確保原鐵水不會過度加熱。Chill Wedge Specifics三角試塊測試特點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.冷鐵測試由于底部寬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。銳角由11.5-34.5度等。在ASTM A 367中，冷鐵尺寸有詳細說明。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.由于碳當(dāng)量影響冷鐵寬度（測量的冷鐵斷面白色區(qū)域的寬度），三角試塊的大小由每個鑄造廠的鑄造化學(xué)成分決定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.低硅原鐵水會呈現(xiàn)完全白色冷鐵除非使用恰當(dāng)?shù)拇蟮娜窃噳K測試。白口鐵寬度至少要占到冷鐵大小的10%。如果較少的話，應(yīng)用更大的冷鐵。如果白口鐵寬度大于50%，激冷就不正確，應(yīng)用更小的冷鐵。一旦冷鐵大小確定，那么底線也就確立。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.在鑄造，冷鐵試塊樣件時，直到三角試樣變?yōu)榘导t色后才能從砂杯里拿出來。然后等到由于空氣冷卻而變成暗桔色并具磁性后放入水中冷卻。Experiences at Farrar在FARRAR公司的經(jīng)驗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個鑄工，原鐵水所用的典型的是，0.75的冷鐵，冷鐵寬度是0.125。這基于所做的多次觀察，確定保持高溫和低溫的效果。還有對于材料比如回爐料，生鐵，以及碳等對金屬的再成核作用所做的實驗。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.如表一的樣品，是在溫度和化學(xué)沒變化的情況下所測結(jié)果?？梢钥闯觯?dāng)溫度持續(xù)保持在一定的值，冷鐵寬度隨著時間的推遲而上升?；诖?，如果金屬在2760F（大概1516攝氏度）下持續(xù)15-20分鐘，在被倒出之前一定會被再成核。 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，金屬被保持在高溫 超過2小時，同時用石墨來維持碳含量。如樣品C、D、E所示，石墨有助于減少冷鐵。然而，結(jié)果很不穩(wěn)定，加少量的生鐵和回爐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也同樣也在上料配比做了實驗，并取冷鐵樣品來確定在三角試樣上所發(fā)生的較明顯的效果。上料配比范圍變化如下，生鐵為14%-21%，廢鋼25%-38%，回爐48%-56%。結(jié)果是：上料配比變化對冷鐵深度未發(fā)現(xiàn)任何明顯影響。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同樣也使用生鐵和它自己的回爐來恢復(fù)成核點。無論是哪種選擇都是同一種結(jié)果，因為當(dāng)重新引入熔煉并恢復(fù)成核，鐵水的0.71%是足夠的。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.時間和溫度對于球鐵來說是成核的敵人。三角試塊是非常重要的一個工具確定在多長時間，多高的溫度線可以保持成核潛力的小事。一旦確立了一個時間界限，那么程序就能確定保證如果超過一定的時間，那么金屬再成核就要跟上。Fig. 1表一These chill wedge samples show that as the melt temperature remainsc