Cutting characteristics of 904L stainless steel

904L stainless steel is high alloying super austenitic stainless steel with very low carbon content. 904L stainless steel has a very good corrosion resistance in dilute sulfuric acid. The participation of copper makes 904L stainless steel has a strong acid resistance, specifically for the corrosion of harsh environment and planning. Therefore, 904L stainless steel is mainly used for the manufacture of corrosion resistant pressure vessels. The main factors of 904L stainless steel are Cr, Ni and other elements, which are difficult to be machined. The main reasons are as follows.

904L stainless steel has greater cutting force than other types of stainless steel. Because 904L hardness is not high (70~90HRB), but it has good plasticity, elongation (> 40%), section compression (> 50%), tensile strength (> 490MPa), yield strength (> 0.2 (> 216MPa), so in the cutting process, its plastic deformation is large, so the cutting force increases.

Low thermal conductivity. The thermal conductivity of 904L stainless steel is 12.9W / (m K) at 20 DEG C, and the thermal conductivity is low. Thermal conductivity is one of the main factors affecting the heat conduction in cutting. The lower the thermal conductivity of the material being processed, the less heat carried away by the chip and the workpiece, and the more heat accumulated on the tool, making the tool wear easily.

Easy to form chip tumors. Because of the toughness of 904L stainless steel, it has a strong affinity with tool material in the cutting process. When cutting, the cutting tool's rake face and the metal at the bottom of the chip will produce strong friction. Under the action of high temperature and high pressure, it will produce adhesion signs, forming chip tumors, and difficult to obtain the machined surface with high surface roughness requirements.

The chip is not easy to bend and break. The elongation of 904L stainless steel is high, so the chip is not easy to bend and break in the cutting process. If not taken the appropriate means, it will affect the normal holding of the cutting process, and easy to scratch the machined surface, and even make the tool break and damage.

Because of the above characteristics of 904L stainless steel, the tool is still easy to wear, the machining efficiency is low, and the workpiece is difficult to reach the surface roughness and machining accuracy required by the drawing even if very small cutting parameters are selected when cutting it with the conventional cutting tools and traditional methods.

The main stainless steel grades are: 201 301 304 304L 309S 310S 316 316L 316Ti 317L 321 347 410 420 430 904L S32205 S31803, etc.