I. Request documentation of the core manufacturing process
This is the most straightforward method. Legitimate manufacturers of compliant 3D welding tables maintain complete records of the heat treatment process. Ask the vendor for the artificial aging heat treatment specification sheet or furnace temperature record report; these should clearly list parameters such as heating temperature, holding time, and cooling procedures. A compliant cast iron welding table typically undergoes artificial aging involving a four-hour soak at approximately 550°C. If the vendor cannot provide these records, it is highly likely that no heat treatment was performed.
II. Assess based on material stress and deformation characteristics
Welding tables that have not undergone heat treatment retain casting-induced internal stresses. Re-check the flatness one to two months after purchase; if the flatness error increases significantly (exceeding factory tolerances by more than 0.05 mm), it is almost certain that no heat treatment was performed. If the precision remains stable after a prolonged period, it indicates that the heat treatment effectively relieved internal stresses.
III. Supplementary verification via hardness testing
Heat treatment adjusts the material hardness to a standard range; the working surface hardness of a compliant cast iron welding table should fall between HB170 and HB255:
Use a hardness tester to measure 3–5 randomly selected points on the working surface. If the hardness deviates significantly from this range, the heat treatment process is likely substandard.
Low-grade cast iron that has not undergone heat treatment typically exhibits hardness well below the standard minimum, making the working surface prone to excessive wear.
IV. Final confirmation via professional stress testing
For a precise determination, contact a third-party testing agency to conduct residual stress testing. In a properly heat-treated welding table, residual internal stress should be ≤20% of the casting's yield strength. Untreated tables exhibit residual stress far exceeding this standard, inevitably leading to deformation during subsequent use.
