带钢冷轧原理简介.ppt

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1、带钢冷轧原理简介带钢冷轧原理简介1 1 1 1提提 纲纲 一、单机架可逆轧机工艺流程一、单机架可逆轧机工艺流程 二、轧制过程的基本概念二、轧制过程的基本概念 三、冷轧工艺简介三、冷轧工艺简介 四、轧制工艺的三大要素四、轧制工艺的三大要素2 2 1 1、单机架可逆轧机工艺流程、单机架可逆轧机工艺流程 酸洗后的热轧钢卷酸洗后的热轧钢卷开卷机开卷开卷机开卷喂料器喂料器 冷轧机轧制冷轧机轧制出口卷取机卷取出口卷取机卷取第二道次开卷第二道次开卷 入口卷取机卷取入口卷取机卷取反复几道次轧制完成反复几道次轧制完成出口出口（或入口）卸卷（或入口）卸卷打捆打捆入库入库3 3-Side guide-Side gu

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36、 Exit Exit Pinch Pinch Pinch Pinch rollrollrollroll2022/11/2516 2 2、轧制过程中的基本概念、轧制过程中的基本概念 1、什么叫加工硬化？、什么叫加工硬化？带钢在冷轧后，晶粒被压扁、拉长、晶格歪扭畸变、带钢在冷轧后，晶粒被压扁、拉长、晶格歪扭畸变、晶粒破碎，使金属的塑性降低、强度和硬度增高，这种晶粒破碎，使金属的塑性降低、强度和硬度增高，这种现象叫做加工硬化。现象叫做加工硬化。冷轧带钢加工硬化后提高了钢的变形抗力，给带钢继冷轧带钢加工硬化后提高了钢的变形抗力，给带钢继续冷轧带来困难。为了消除加工硬化，大多数带钢必须续冷轧带来困难。为

37、了消除加工硬化，大多数带钢必须在加工过程中进行再结晶退火（软化退火和中间退火）。在加工过程中进行再结晶退火（软化退火和中间退火）。2、什么是塑性？、什么是塑性？塑性，是指金属在外力作用下，能稳定地发生永久变塑性，是指金属在外力作用下，能稳定地发生永久变形而不破坏其完整性的能力形而不破坏其完整性的能力。1717 3 3、轧制过程的描述？、轧制过程的描述？轧制过程是靠旋转的轧辊与轧件之间形成的摩擦力将轧制过程是靠旋转的轧辊与轧件之间形成的摩擦力将轧件拖进辊缝之间，并使之受到压缩产生塑性变形的过轧件拖进辊缝之间，并使之受到压缩产生塑性变形的过程，通过轧制使金属具有一定的尺寸、形状和性能。程，通过轧制

38、使金属具有一定的尺寸、形状和性能。4、轧制变形区的主要参数？、轧制变形区的主要参数？1818 咬入角：咬入角：轧制时轧件与轧辊表面接触的弧线叫做咬入轧制时轧件与轧辊表面接触的弧线叫做咬入弧。咬入弧所对的圆心角叫做咬入角。咬入角由压下量确弧。咬入弧所对的圆心角叫做咬入角。咬入角由压下量确定。在不同轧制条件下，最大允许咬入角是不同的，其大定。在不同轧制条件下，最大允许咬入角是不同的，其大小与轧辊表面和轧件的表面状态、轧制温度以及轧辊转速小与轧辊表面和轧件的表面状态、轧制温度以及轧辊转速等因素有关，即与轧辊和轧件间摩擦系数有关。等因素有关，即与轧辊和轧件间摩擦系数有关。变形程度表示方法：变形程度表示

39、方法：绝对变形量和相对变形量绝对变形量和相对变形量 绝对变形量：绝对变形量：厚度（高度）：轧前厚度厚度（高度）：轧前厚度H，轧后厚度，轧后厚度h，压下量，压下量h 轧辊直径轧辊直径 D 轧辊半径轧辊半径 R h=H-h=2（R R cos）=D（1 cos）相对变形量相对变形量（变形程度）：（变形程度）：压下率压下率=H-h/H 1919 最小可轧厚度：最小可轧厚度：生产实践表明，在一定轧机上轧制某种产品时候，随生产实践表明，在一定轧机上轧制某种产品时候，随着带钢的逐渐变薄，压下愈来愈困难，当带钢厚度薄到某着带钢的逐渐变薄，压下愈来愈困难，当带钢厚度薄到某一限度后，不管如何加大液压压下的压力，

40、不管反复轧制一限度后，不管如何加大液压压下的压力，不管反复轧制多少道，也不可能再使产品轧薄。这时带钢的极限厚度称多少道，也不可能再使产品轧薄。这时带钢的极限厚度称为最小可轧厚度。为最小可轧厚度。带钢最小可轧厚度主要由轧机工作辊直径决定，同时带钢最小可轧厚度主要由轧机工作辊直径决定，同时还与金属材料的性质、张力、润滑情况、轧辊材料等因素还与金属材料的性质、张力、润滑情况、轧辊材料等因素有关。有关。工作辊辊径与成品带材厚度的比例关系为：工作辊辊径与成品带材厚度的比例关系为：D2000h20203.1 什么是冷轧？冷轧带钢有哪些优点？什么是冷轧？冷轧带钢有哪些优点？金属在再结晶温度以下进行轧制变形叫

41、做冷轧。一般指金属在再结晶温度以下进行轧制变形叫做冷轧。一般指带钢不经加热而在室温直接进行轧制加工。冷轧后的带钢带钢不经加热而在室温直接进行轧制加工。冷轧后的带钢可能烫手，但还是叫冷轧。可能烫手，但还是叫冷轧。冷轧生产可提供大量高精确度和性能优良的钢板和带材，冷轧生产可提供大量高精确度和性能优良的钢板和带材，其最主要的特点是加工温度低，同热轧生产相比，它有以其最主要的特点是加工温度低，同热轧生产相比，它有以下有点：下有点：1）冷轧带钢产品尺寸精确，厚度均匀，带钢厚度差一般冷轧带钢产品尺寸精确，厚度均匀，带钢厚度差一般不超过不超过0.010.03mm或更小，完全可以符合高精度公差的或更小，完全可

42、以符合高精度公差的要求。要求。2）可获得热轧无法生产的极薄带材（最薄可达可获得热轧无法生产的极薄带材（最薄可达0.001mm以下）。以下）。3 3 冷轧工艺冷轧工艺2121 3）冷轧产品表面质量优越，不存在热轧带钢常常出现的麻冷轧产品表面质量优越，不存在热轧带钢常常出现的麻点、压入氧化铁皮等缺陷，并且可根据用户的要求，生产出点、压入氧化铁皮等缺陷，并且可根据用户的要求，生产出不同表面粗糙度的带钢（光泽面或麻糙面等），以利于下道不同表面粗糙度的带钢（光泽面或麻糙面等），以利于下道工序的加工。工序的加工。4）冷轧带钢具有很好的力学性能和工艺性能（如较高的强冷轧带钢具有很好的力学性能和工艺性能（如较

43、高的强度、较低的屈服极限、良好的深冲性能等）。度、较低的屈服极限、良好的深冲性能等）。5）可实现高速轧制和全连续轧制，具有很高的生产率。可实现高速轧制和全连续轧制，具有很高的生产率。3.2 冷轧带钢的轧制工艺有哪些特点？冷轧带钢的轧制工艺有哪些特点？1）带钢在轧制过程中产生不同程度的加工硬化。加工硬化带钢在轧制过程中产生不同程度的加工硬化。加工硬化超过一定程度后，带钢因过分硬脆而不适于继续轧制。因此超过一定程度后，带钢因过分硬脆而不适于继续轧制。因此带钢经冷轧一定的道次（即完成一定的冷轧总压下量）之带钢经冷轧一定的道次（即完成一定的冷轧总压下量）之后，往往要经过软化热处理（再结晶退火等），使轧

44、件恢复后，往往要经过软化热处理（再结晶退火等），使轧件恢复塑性，降低变形抗力，以便继续轧薄。塑性，降低变形抗力，以便继续轧薄。2222 2）冷轧过程必须采用工艺冷却和润滑。冷轧带钢的变形功冷轧过程必须采用工艺冷却和润滑。冷轧带钢的变形功约有约有8488转变为热能，使带钢与轧辊的温度升高，转变为热能，使带钢与轧辊的温度升高，故故须采用冷却措施。采用工艺润滑的主要作用是减小金属的变须采用冷却措施。采用工艺润滑的主要作用是减小金属的变形抗力，这样在已有的轧机能力条件下实现更大的压下，还形抗力，这样在已有的轧机能力条件下实现更大的压下，还可使轧机生产出更薄的产品。可使轧机生产出更薄的产品。3）冷轧中采

45、用张力轧制。张力轧制就是带钢在轧辊中轧制冷轧中采用张力轧制。张力轧制就是带钢在轧辊中轧制变形是在一定前张力和后张力作用下进行的。变形是在一定前张力和后张力作用下进行的。张力的作用主要是：防止带钢在轧制过程中跑偏（即保张力的作用主要是：防止带钢在轧制过程中跑偏（即保证正确对中轧制）；使所轧带钢保持平直（包括在轧制过程证正确对中轧制）；使所轧带钢保持平直（包括在轧制过程中保持板形平直和轧后板形良好）；降低金属的变形抗力，中保持板形平直和轧后板形良好）；降低金属的变形抗力，有利于轧制更薄的产品，起适当调整冷轧机主电机负荷的作有利于轧制更薄的产品，起适当调整冷轧机主电机负荷的作用。用。2323 3.3

46、影响冷轧轧制压力的因素有哪些？影响冷轧轧制压力的因素有哪些？影响轧制压力的因素很多，基本上可以分为两大类。影响轧制压力的因素很多，基本上可以分为两大类。一类是影响金属变形阻力的，其中有金属材料的化学成分、一类是影响金属变形阻力的，其中有金属材料的化学成分、变形温度与变形程度，金属变形阻力增高，将使压力加大。变形温度与变形程度，金属变形阻力增高，将使压力加大。第二类是影响应力状态条件的因素，其中有外摩擦（即摩第二类是影响应力状态条件的因素，其中有外摩擦（即摩擦系数）、轧件及轧辊直径、张力等。擦系数）、轧件及轧辊直径、张力等。1）钢种不同，即金属材料化学成分不同，材料本身力）钢种不同，即金属材料化

47、学成分不同，材料本身力学性能不同，因而变形阻力不同。学性能不同，因而变形阻力不同。2）变形程度的影响也就是加工硬化的影响。金属塑性）变形程度的影响也就是加工硬化的影响。金属塑性变形时，其形状变化能量大部分用于塑性变形，以热的形变形时，其形状变化能量大部分用于塑性变形，以热的形式存在；另外一部分则产生晶格扭转、位错等，内能增式存在；另外一部分则产生晶格扭转、位错等，内能增高，这部分保留在金属中的能量叫做残留畸变能，此能量高，这部分保留在金属中的能量叫做残留畸变能，此能量使金属的变形阻力增加，出现加工硬化现象。使金属的变形阻力增加，出现加工硬化现象。2424 3）随着变形温度的升高，变形阻力降低。

48、随着变形速度）随着变形温度的升高，变形阻力降低。随着变形速度的提高，变形阻力将增加。但对冷轧来说，其影响不很显著。的提高，变形阻力将增加。但对冷轧来说，其影响不很显著。4）摩擦力越大，压力也越大。粗糙表面轧辊的摩擦系数）摩擦力越大，压力也越大。粗糙表面轧辊的摩擦系数比光滑表面轧辊高，所以压力也大。比光滑表面轧辊高，所以压力也大。5）轧件厚度和轧辊直径的影响。）轧件厚度和轧辊直径的影响。6）张力的影响。带钢的前后张力都使单位压力降低，且）张力的影响。带钢的前后张力都使单位压力降低，且后张力影响更为明显。由于存在张力，变形区内金属在轧制后张力影响更为明显。由于存在张力，变形区内金属在轧制方向产生附

49、加拉应力，此拉应力引起轧制时三向压应力状态方向产生附加拉应力，此拉应力引起轧制时三向压应力状态的水平方向主应力减小，从而降低了单位压力。因中性面偏的水平方向主应力减小，从而降低了单位压力。因中性面偏向带钢出口，故后张力影响大于前张力。向带钢出口，故后张力影响大于前张力。2525 4、冷轧的三大要素冷轧的三大要素-轧制工艺、轧辊、乳化液轧制工艺、轧辊、乳化液 4.1 4.1 轧制工艺轧制工艺26264.1.1怎样确定编制轧制表？怎样确定编制轧制表？轧制表是冷轧工艺的主要内容之一，它关系到是否轧制表是冷轧工艺的主要内容之一，它关系到是否能获得合乎要求的产品、产量、能耗及成本。轧制表包括：能获得合乎

50、要求的产品、产量、能耗及成本。轧制表包括：总压下率、道次压下率、前后张力、轧制速度、轧辊辊径总压下率、道次压下率、前后张力、轧制速度、轧辊辊径和辊形等。制定轧制表主要依据是：带材交货标准的各项和辊形等。制定轧制表主要依据是：带材交货标准的各项要求，用户提出的特殊要求，以及设备能力和生产要求等要求，用户提出的特殊要求，以及设备能力和生产要求等因素。因素。首先，选择冷带钢原料厚度通常要考虑成品带材的质首先，选择冷带钢原料厚度通常要考虑成品带材的质量要求，包括组织性能和表面质量。选择原料厚度主要考量要求，包括组织性能和表面质量。选择原料厚度主要考虑冷轧总压下率，因为对一定钢种、规格的产品，必须有虑冷