Custom Sheet Metal Deformation Causes

Throughout the entire process of custom mechanical sheet metal processing, from steel rolling and forming to subsequent assembly and welding, sheet metal workpieces are constantly subjected to external forces such as mechanical processing and hoisting, and also undergo process steps like heating deformation processing. Stress and deformation are inevitable during this process.

Among them, deformation that meets the product technical requirements is necessary for processing, while stress and deformation beyond the specifications are deformation defects that will directly affect the quality of sheet metal workpieces.

Accurate identification of core deformation causes in sheet metal processing underpins effective technical and process defect control.

Below: detailed analysis of sheet metal deformation triggers in raw material and part processing phases.

Raw Material Stage: Congenital Deformation Caused by Improper Rolling, Storage and Transportation

Deformation problems in sheet metal processing often originate at the raw material stage. Such congenital deformation is mainly caused by non-standard operations in steel rolling, transportation and stacking, with process issues in the rolling process being the core inducement.

Steel rolling: uneven heating, roll bending and inconsistent gaps cause widthwise uneven sheet pressure.

Uneven pressure causes differences in the elongation of various parts of the sheet: the parts with greater elongation are constrained by those with less elongation, thus generating compressive stress, while the parts with less elongation generate tensile stress. Sustained compressive stress causes the more elongated sheet sections to lose structural stability, eventually forming leek-like deformation defects.

In addition to the rolling process, the cooling link after hot rolling is also highly prone to causing raw material deformation.

If the hot-rolled steel is not properly protected and is exposed to moisture or directly to water, the abrupt changes in temperature and humidity will disrupt the internal stress distribution of the steel, resulting in deformation.

Furthermore, collisions and stacking during steel transportation, as well as incorrect stacking in the warehousing stage, will subject the raw materials to additional external forces, causing initial deformation problems and laying hidden quality dangers for subsequent processing.

Processing Stage: Differential Deformation Problems in Different Profiles

In sheet metal part processing, varying profile specifications and thicknesses lead to distinct stress conditions, resulting in different deformation characteristics.

Thin sheet parts, in particular, have more prominent deformation problems.

Thin sheet metal parts: high deformation risk, with local unevenness, wrinkling and mild large-wave deformation. Such deformation will directly affect the flatness of the parts and the accuracy of subsequent assembly.

For large industrial steel, transverse wave-like bending is likely to occur during processing, and torsional deformation may also happen in some cases, which are more difficult to adjust and repair; large-sized channel steel is mainly characterized by bending deformation during processing; while small-sized angle steel is often subject to distortion and deformation. Different profiles exhibit distinct deformation characteristics, which call for tailored stress control measures during processing.

Deformation defects span sheet metal processing stages, with varying causes and forms by link and profile.

Only by pinpointing these deformation factors precisely can we implement targeted process improvements and prevention measures, minimizing deformation defects at the source. In subsequent parts, we will share sheet metal deformation prevention and control skills to improve machining quality of workpieces.