Stainless steel material analysis and grinding guide

+ 查看更多

Stainless steel is a versatile material, categorized into two main types based on its composition: chromium stainless steel and chromium-nickel stainless steel. Furthermore, it can be classified into five internal structures:

1. Martensitic Stainless Steel (Common grades include 1Cr13, 2Cr13, 8Cr13, 1Cr17Ni2, etc.)

2. Ferritic Stainless Steel (Common grades include 0Cr13, 1Cr14S, 1Cr17, 1Cr17Ti, etc.)

3. Austenitic Stainless Steel (Common grades include 1Cr18Ni9Ti, 0Cr18Ni9, 1Cr18Ni9, etc.)

4. Austenitic-Ferritic Stainless Steel (Common grades include 1Cr18Ni11Si4AlTi, 0Cr21Ni5Ti, etc.)

5. Precipitation Hardening Stainless Steel (Common grades include 0Cr17NiCu4Nb, 0Cu17Ni7Al, 0Cr15Ni7Mo2Al, etc.)

Grinding Characteristics

1. a. Strong Grinding Force, High Temperature: Grinding stainless steel involves significant force and generates high temperatures.

b. Severe Hardening: The material tends to harden during processing.

c. Chip Adhesion to the Grinding Wheel: Chips from the material tend to stick to the grinding wheel.

d. Difficult Chip Removal, Abrasive Blunting: Chips are challenging to remove, and the abrasive particles are prone to dulling.

e. Surface Prone to Scratches: The workpiece surface is susceptible to scratching.

f. Workpiece Deformation: The workpiece can undergo deformation.

Choosing the Grinding Wheel

1. a. Abrasive Material: White Fused Alumina (WA) is generally suitable. Cubic Boron Nitride (CBN) grinding wheels (with 120-grit, 100% concentration, and resin bonding) offer the best grinding performance, minimizing the risk of workpiece burn. However, they are more expensive and harder to dress. Single Crystal Alumina (SA) works well for grinding acid-resistant stainless steel, and Microcrystalline Alumina (MA) is suitable for grinding Cr17Ni7Al precipitation-hardening stainless steel.

b. Grit Size: Due to the toughness of stainless steel, finer-grit wheels are not recommended. Coarse grinding benefits from grit sizes like F36 and F46, while finer grinding can use F60 grit. To accommodate both coarse and fine grinding, F46 and F60 grit sizes are recommended.

c. Bond Type: Ceramic bonding is a suitable option. It offers high water resistance, heat resistance, and corrosion resistance, maintaining cutting performance effectively. Additionally, it provides porosity, leading to higher productivity.

d. Hardness: Opt for a grinding wheel with a lower hardness, as it maintains good self-sharpening properties. However, if the wheel's hardness is too low, abrasive grains may not bond well and could detach prematurely, significantly reducing the wheel's lifespan. Hence, choosing wheels within the range of J3 to N2 is generally appropriate, with K1 and K2 being the most commonly used.

e. Structure: When grinding stainless steel, it's important to select a wheel structure between F5 and F8, as these are less likely to clog. Wheels with open pores are preferable for production purposes.

f. Coolant: Emulsion or Type 1 cutting fluids with good cooling and cleansing properties are recommended.

Understanding the various types of stainless steel and their grinding characteristics is crucial for achieving optimal results in metalworking applications.