The main characteristics of stainless steel turned parts are high machining difficulty and demanding requirements for cutting tools and processes. The core challenges stem from the material's high toughness, low thermal conductivity, and easy work hardening properties.
Compared to carbon steel, stainless steel exhibits significantly different physical and mechanical behaviors during turning, directly impacting machining efficiency, tool life, and part quality. The following is a detailed analysis of these characteristics:
High cutting force and high cutting temperature: Stainless steel (especially austenitic types such as 304 and 1Cr18Ni9Ti) has high strength and plasticity, resulting in large plastic deformation during cutting. This leads to a unit cutting force that is more than 25% higher than that of 45 steel. Simultaneously, its thermal conductivity is only 1/3 to 1/4 that of 45 steel, making heat dissipation difficult. This results in cutting zone temperatures that can be more than 200°C higher than those of ordinary steel, and locally reach 1000°C, accelerating tool wear.
Second, prone to work hardening: Austenitic stainless steel rapidly undergoes work hardening during cutting. The hardened layer can reach more than 1/3 of the cutting depth, increasing hardness by 1.4 to 2.2 times and strength to 1470 to 1960 MPa. This means that subsequent tool cutting is actually on a "hardened layer," significantly shortening tool life and increasing the risk of chipping.
Prominent Issues of Chip Adhesion and "Built Edge" Stainless steel exhibits strong affinity with cutting tool materials under high temperature and pressure, causing chips to easily adhere to the rake face, forming a "built edge," which affects surface finish and induces vibration. This continuous, "chewing gum-like" chipping can also entangle the workpiece, scratching the machined surface and even causing safety accidents.
Difficult Chip Breaking and Poor Chip Removal Stainless steel has good plasticity, easily producing long, continuous ribbon-like chips during cutting, making chip removal difficult. Especially in deep hole drilling or automated production lines, chip accumulation affects cooling efficiency, accelerates tool wear, and can even clog the machining area. Therefore, reliable chip breaking must be achieved through chip breaker design or parameter adjustment.
