抗熱裂
通常對粗軋輥以強(qiáng)度、抗熱裂為主要要求;小型20輥軋機(jī)的工作軋輥重僅 100克左右,而寬厚板軋機(jī)的支承輥重量已超過200噸。選用軋輥時(shí)首先根據(jù)軋機(jī)對軋輥的基本強(qiáng)度要求,選定安全承載的主體材料(各種級別的鑄鐵、鑄鋼或鍛鋼等)。
硬度
而精軋輥速度較高,軋制最終產(chǎn)品要有一定的表面質(zhì)量,對它以硬度、耐磨等為主要要求。然后考慮軋輥使用時(shí)所應(yīng)有的耐磨性。由于軋輥的磨損機(jī)理很復(fù)雜,包括機(jī)械應(yīng)力作用、軋制時(shí)的熱作用、冷卻作用、潤滑介質(zhì)的化學(xué)作用以及其他作用,還沒有一項(xiàng)綜合評定軋輥抗磨性的統(tǒng)一指標(biāo)。由于硬度易于測量,并在一定條件下可以反映耐磨性,所以一般就用徑向硬度曲線來近似地表述軋輥的耐磨指標(biāo)。
耐沖擊
此外,對軋輥還有一些特殊要求,如壓下量大時(shí),要求軋輥有較強(qiáng)的咬入能力,較耐沖擊;
光潔度
軋制薄規(guī)格產(chǎn)品時(shí),則對軋輥的剛性、組織性能均勻性、加工精度以及表面光潔度等要求較嚴(yán);
切削性能
軋制復(fù)雜斷面的型鋼時(shí),還要考慮輥身工作層的切削加工性能等。
選用軋輥時(shí),對軋輥的有些性能要求往往是彼此對立的,軋輥購置費(fèi)和維護(hù)費(fèi)用又很昂貴,所以應(yīng)充分權(quán)衡技術(shù)和經(jīng)濟(jì)上的利弊,決定用鑄的還是鍛的,合金的還是非合金的,單一材料的還是復(fù)合材料的。
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Resistance to hot cracking
Generally, the rough roll is mainly required for strength and thermal crack resistance; the work roll of the small 20-roll mill has a weight of only about 100 grams, and the weight of the support roll of the wide plate mill has exceeded 200 tons. When selecting the rolls, the main material of the safety bearing (all grades of cast iron, cast steel or forged steel, etc.) is selected according to the basic strength requirements of the rolling mill.
hardness
The finishing roll speed is higher, and the final product to be rolled must have a certain surface quality, and it is mainly required for hardness and wear resistance. Then consider the wear resistance that should be used when the rolls are used. Due to the complex wear mechanism of the rolls, including mechanical stress, thermal action during rolling, cooling, chemical action of the lubricating medium, and other effects, there is no uniform indicator for comprehensive evaluation of roll wear resistance. Since the hardness is easy to measure and can reflect the wear resistance under certain conditions, the radial hardness curve is generally used to approximate the wear resistance index of the roll.
Shock proof
In addition, there are some special requirements for the rolls. For example, when the amount of pressing is large, the rolls are required to have a strong biting ability and are more resistant to impact;
Finish
When rolling thin gauge products, the requirements for the rigidity, uniformity of the structure, processing accuracy and surface finish of the rolls are stricter;
Cutting performance
When rolling a profiled section of a section, it is also necessary to consider the cutting performance of the working layer of the roll body.
When using rolls, some performance requirements of the rolls are often opposite to each other. The roll purchase cost and maintenance cost are very expensive. Therefore, the technical and economic advantages and disadvantages should be fully weighed, and whether the cast or forged, alloy or non-alloy is decided. , single material or composite.