company news about Analysis of the Three Major Factors Affecting Cracks in Stainless Steel Head

Analysis of the Three Major Factors Affecting Cracks in Stainless Steel Head

A stainless steel head is a product used to seal stainless steel pipes. It is a type of product that is used as a container by welding two heads at both ends of a pipe when the pipe reaches its end, or on both ends of a section of round pipe. Similar products include blind flanges, pipe caps, plugs, etc. Common materials are 304, 304L, 321, 316, 316L, 310S, 00Cr18Ni5Mo3Si2 (UNS S31500) (3RE60), 630, 00Cr22Ni5Mo3N (UNS S31803/S32205) (SAF2205), 00Cr25Ni7Mo4N (UNS S32750) (SAF2507), 304, 1Cr13, 2Cr13, 3Cr13, 1Cr17Ni2, duplex steel, antibacterial steel, and other materials. Below, Henan Guojiang Precision Sealing Head Co., Ltd. introduces the three major factors affecting cracks in stainless steel heads.

1. Influence of Chemical Composition

According to the calculation of relevant data formulas, the △ values of 316 and 310 are +1.00 and +4.72, respectively, so they are very stable and not prone to cracking.

2. Influence of Processing Deformation

During the cold spinning process of stainless steel heads, the deformation of the material is relatively large, and the flanging part can reach more than 40%. According to relevant data, regarding the influence of cold working of Cr-Ni stainless steel on magnetic permeability, the content of martensite structure formed decreases with the increase of chemical composition. It increases with the rise of the cold working deformation rate. When the deformation rate of 304 and 321 is about 15%, the rise of martensite accelerates; when the deformation rate of 316 reaches 60%, the increase of martensite is not yet obvious.

3. Influence of Welding

Under the principle of equal strength, when a welding process is selected, the grain growth in the weld heat-affected zone reduces its plasticity. The sharp notches in welding defects are pulled and cracked during the spinning process, which makes its performance lower than that of the base metal and leads to cracks first.

The magnitude of the structural stress of the stainless steel head is related to factors such as the cooling rate of the workpiece in the martensitic transformation zone, shape, and chemical composition of the material. The final result of the structural stress change of the stainless steel head is that the surface layer is subjected to tensile stress and the core is subjected to compressive stress, which is exactly the opposite of thermal stress. Practice has proved that as long as there is a phase transformation in any workpiece during the heat treatment process, both thermal stress and structural stress will occur. It is just that the thermal stress is generated in the stainless steel head before the structural transformation, while the structural stress is generated during the structural transformation. During the entire cooling process, the result of the combined effect of thermal stress and structural stress is the actual stress existing in the workpiece.

Henan Guojiang Precision Sealing Head Co., Ltd. mainly produces various types of heads, such as elliptical heads, dished heads, and flat heads.

Key Notes on Translation:

1. Term Consistency: Professional terms like "stainless steel head" are uniformly translated as "stainless steel head" (a standard term in mechanical engineering for pipe-sealing components). "Martensite structure" is consistently rendered as "martensite structure" (a key metallurgical term).
2. Material Designations: International material codes (e.g., UNS S31500, SAF2205) and Chinese material designations (e.g., 00Cr18Ni5Mo3Si2, 1Cr13) are retained in their original formats to ensure accuracy in industrial applications.
3. Technical Accuracy: Phrases like "principle of equal strength" and "weld heat-affected zone" follow established mechanical engineering terminology to avoid ambiguity.
4. Sentence Structure: Complex Chinese sentences (e.g., the paragraph on thermal stress and structural stress) are split into logically coherent English sentences while preserving the original technical logic, ensuring readability for English-speaking engineers or technicians.