Necessary conditions for stress corrosion cracking of stainless steel rods

The necessary conditions for stress corrosion cracking of stainless steel rods and wires are tensile stress and the presence of specified corrosive substances. The establishment and expansion of the pattern may be perpendicular to the direction of tensile stress. This internal stress value that causes stress corrosion cracking is much smaller than the internal stress value necessary for the material to break when no corrosive substances are present. In the external economy, cracks that cross the crystal are called transgranular cracks, and cracks that expand along the dislocation pattern are called intergranular cracks. When stress corrosion cracking expands to one of its depths, the material behaves like a normal crack. (In ductile materials, this is usually caused by the convergence of microscopic defects). Thus, a cross-section of a part that fails due to stress corrosion cracking will contain areas characteristic of stress corrosion cracking and "dimple" areas associated with the accumulation of micro-defects. Pitting corrosion: is a form of partial corrosion that causes corrosion.

DDQ material: refers to the raw material used for deep drawing, which is what we refer to as soft material. The main characteristics of this type of material are high tensile strength (≧53%) and low strength (≦ 170%), the internal crystal level is between 7.0 and 8.0, and the deep drawing characteristics are excellent. Many companies that produce boiling water bottles and pots generally have very high product processing ratios (BLANKINGSIZE/product diameter), with their processing ratios reaching 3.0, 1.96, 2.13, and 1.98 respectively. The material SUS304DDQ is mainly used for products that require a higher processing ratio. Of course, products with a processing ratio exceeding 2.0 generally need to be stretched several times before they can be completed. If the raw material expansion level is not up to standard, the product will easily cause cracks and pull-through during the processing of deep-drawn products, which will affect the compliance rate of the finished product and naturally increase the manufacturer's cost.