A. Sample and material numbering
a.Familiarize with the construction drawings, and contact the relevant technical department to solve the problem if you find any doubt.
b.Prepare materials for sample plate and sample rod, generally thin iron and small flat steel can be used.
c.The steel ruler needed for sample placement must be checked and reviewed by the measurement department and can be used only after passing.
d. Before the number of materials must understand the material and specifications of raw materials, check the quality of raw materials. Different specifications, different materials of the parts should be numbered material.
e. Sample sample rod on the application of paint processing number, component number, specifications, while marking the diameter of the upper hole, work line, bending line and other processing symbols.
f. Sample placement and numbering should be reserved for shrinkage (including on-site welding shrinkage) and cutting, milling end and other required machining allowance.
Milling end allowance: shear after processing generally add 3-4mm per side, gas cutting after processing then adds 4-5 mm per side.
Cutting allowance: 3mm for automatic gas cutting and 4mm for manual gas cutting.
The welding shrinkage is given by the process according to the structural characteristics of the member.
g. The main force members and the need to bend the members, in the number of material should be taken in the direction of the process, the outer side of the bent parts should not have the same punch point and scar defects.
h. The number of materials should be conducive to cutting and ensure the quality of parts.
i. The remaining material after the number should be marked, including the residual material number, specification, material and furnace batch number, etc., so as to facilitate the use of the residual material again.
After undercutting and scribing, the steel must be undercut according to its desired shape and size.
a. The following points should be noted when cutting.
When a steel plate is arranged on many parts and several intersecting shear lines, should be prearranged to a reasonable shear program before shearing.
Material bending deformation after shearing must be corrected; shear surface rough or with burrs, must be repaired polished
shearing process, the metal near the cut, extrusion and bending due to shear, important structural components and the interface location of the weld, must be used to milling, planing or grinding wheel grinding and other methods.
b. The following construction points should be noted in the construction of sewing machinery.
Section steel should be straightened before sawing.
Single sawing components, first scribe the number line, and then sawing on the line. Batch processing of components can be pre-installed positioning stopper processing.
Machining accuracy requirements of important components should be considered to reserve an appropriate amount of machining allowance for sawing after the end face finish milling.
When sawing, attention should be paid to the control of the verticality of the cutting section.
c. The following process points should be noted when performing gas cutting operations.
Before gas cutting, all equipment and tools of the whole gas cutting system must be checked and confirmed to be in normal operation and ensure safety.
The correct process parameters should be selected during gas cutting. When cutting, the shape of oxygen jet (wind line) should be adjusted so that it can reach and maintain clear contour, long wind line and high shooting force.
Before gas cutting, the dirt, oil and floating rust and other debris should be removed from the steel surface, and a certain space should be left underneath to facilitate the blowing out of slag.
When gas cutting, tempering must be prevented.
In order to prevent the deformation of gas cutting, the operation should start from the short side first; should cut the small pieces first, and then cut the large pieces; should cut the more complicated ones first, and then cut the simpler ones.