1. Expansion wire of bottom brick of tin bath:
① The expansion wire used in our factory is 3mm, 4mm, 5mm and other three specifications of iron wire, and the acceptance standard is 0-0.2mm. If it is a negative tolerance, the force of knocking the bottom brick with a wooden hammer during laying shall not be too large to avoid the expansion joint becoming smaller.
② The bent expansion wire shall be stored by classification without confusion. When using, put two ends of 10 mm into the bottom brick joint. If the expansion wire is accidentally dropped into the brick joint, it shall be taken out in time.
③ Each section of the iron wire about 120mm shall be cut off, bent into "U" shape first, and then two ends about 10 mm long shall be bent to one side to form an angle of about 90 °
④ The extraction process shall be carried out after the completion of hole sealing material ramming. Insert a tool into the hole of the expansion wire and pull out the expansion wire with slight force. If the force is too large, the expansion wire shall be pulled to break (3mm expansion wire is easy to break), and the broken part shall be taken out in time. After the extraction of the expansion wire of the whole tin bath, the extraction of the expansion wire shall be inspected: a thin iron sheet with a length of about 500 mm, a width of about 50 mm and a thickness of 1-2 mm shall be used to extend into the bottom brick gap (as far as possible to the bottom of the brick), and it is qualified if it is pulled horizontally and longitudinally along the gap without obstruction.
2. Metal gasket for bottom brick of tin bath:
The metal gasket used for the bottom brick should meet two aspects: one is to meet the depth of the tin liquid; the other is to meet the requirement of the tightness of the bottom brick of the tin bath. Less is better. In the process of tin bath heating up, the steel plate is heated and affected by the horizontal and vertical expansion force of the bottom brick of the tin bath. There is a trend of stretching and flattening. If there is metal gasket, on the contrary, it will hinder this trend, so that the gap between the steel plate and the bottom brick will exist permanently, laying a hidden danger for the occurrence of tin leakage and bottom brick floating accident.
When laying the bottom brick of the tin bath, the following conditions will occur:
① The bottom brick of the tin bath has good stability (press any corner of the four corners of the bottom brick of the tin bath with force, the other parts of the bottom brick have no warping phenomenon), but there is a gap between the bottom brick and the steel plate;
② The stability of the bottom brick of the tin bath is poor, and there is a gap between the bottom brick and the steel plate.
According to the previous description, in the first case, the bottom brick has good stability and does not need to be padded with metal gasket under the bottom brick. In the second case, first find out the cause. If it is caused by the unevenness of the bottom surface of the bottom brick of the tin bath, the bottom brick shall be ground flat by the grinder, and no metal gasket is needed. If the local deformation of the steel plate is serious (mainly refers to the old steel plate during cold repair), in order to meet the stability requirements, it is necessary to pad the corresponding thickness of metal gasket under the bottom brick of the tin bath.
