镀锌板冲压开裂的预防措施分析
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镀锌线的生产工艺为:冷硬辊→脱脂→连续退火→镀锌→精整→矫直→辊涂→感应加热→风冷→质量检验→涂油、称重、包装。在其生产过程中,容易出现冲压裂纹,影响用户的生产。原因如下:
一。退火温度
退火温度是镀锌过程中的一个重要参数,对产品的屈服强度有很大的影响。当退火温度较低时,退火不足,晶粒细小,强度较高,延伸率较低;当退火温度过高时,晶粒易出现异常粗化,屈服强度降低,抗拉强度下降更严重,而且产品在客户的冲压和拉拔过程中容易直接断裂。
2。机加工润滑
材料的表面粗糙度将影响其表面的储油能力。适当的钢卷表面粗糙度对材料的冲压性能也非常重要。同时,油量的选择也非常重要。如果油量太少,材料在冲压过程中润滑不足,会导致材料冲压开裂;如果油量太大,在分切成形过程中容易打滑,影响生产节奏。
三。材料厚度和模具间隙配合
在冲压过程中,模具间隙与材料厚度的匹配也是导致材料开裂的重要因素。
四。夹杂物和其他缺陷的控制
夹杂、异物压入等缺陷对冲压件的冲压成形非常不利。由于夹杂部分的局部延伸率不够,容易产生冲压和拉伸开裂。
根据以上分析,为避免镀锌板冲压开裂,可采取以下措施
一。钢厂应设置合理的镀锌退火温度,目标值应控制在850℃左右,并保证温度控制的稳定性;
2。选择合适的防锈油进行冲压,并给出合理的油量;
三。抛光机轧制力控制在1200千牛以上;
。炼钢过程中应控制夹杂物,保证钢液的清洁;
5个。充分了解模具使用情况,确保模具间隙、材料变形能力和材料厚度的匹配。
The production process of galvanizing line is as follows: cold hard roll → degreasing → continuous annealing → galvanizing → finishing → straightening → roller coating → induction heating → air cooling → quality inspection → oiling, weighing and packing.
In its production, stamping cracks are easy to appear, which affects the production of users. The causes are as follows:
1. Annealing temperature
Annealing temperature is an important parameter in galvanizing process, which has a great influence on yield strength of products. When the annealing temperature is low, the annealing is not sufficient, the grains are small,
the strength is high, and the elongation is low; when the annealing temperature is too high, the grains are easy to be abnormally coarse, the yield strength is reduced, and the tensile strength is decreased more severely, and the products are easy to
break directly in the stamping and drawing process of customers.
2. Machining lubrication
The surface roughness of the material will affect the oil storage capacity of its surface. The appropriate surface roughness of the steel coil is also very important for the stamping performance of the material. At the same time, the choice of
the amount of oil is very important. If the amount of oil is too small, the material will not be sufficiently lubricated in the stamping process, which will lead to the material stamping cracking; if the amount of oil is too large, it will easily slip
in the process of slitting and forming, which will affect the production rhythm.
3. Material thickness and die clearance fit
In the stamping process, the matching of die gap and material thickness is also an important factor that leads to
material cracking.
4. Control of inclusions and other defects
The defects such as inclusion and foreign matter press in are very unfavorable to the stamping forming of stamping products. Because the local elongation of the inclusion part is
not enough, it is easy to produce stamping and tensile cracking.
According to the above analysis, the following measures can be taken to avoid stamping cracking of galvanized sheet:
1. The steel plant should set reasonable annealing temperature
for galvanizing, the target value should be controlled at about 850 ℃, and the stability of temperature control should be ensured;
2. Select the right anti rust oil for stamping and give a reasonable amount of oil;
3. The rolling force of
the polishing machine shall be controlled above 1200kN;
4. Inclusions shall be controlled in the steel-making process to ensure the cleanliness of the molten steel;
5. Fully understand the mold used to ensure the matching of mold clearance,
material deformation ability and material thickness.