Making stainless steel easier to machine

Stainless steel is one of the more difficult materials to process. Adding sulfur to such as austenitic steel (such as 303) to reduce machinability, it is still easy to form cutting edges, it is difficult to maintain a good surface finish of the part and shorten the tool life. Reducing the amount of sulfur added as needed for 304 and 316 makes these problems worse and reduces chip generation. After searching at high altitude, the alchemist found a recipe for turning lead into gold.Steel producers are looking for a stainless steel formulation to make these materials more mechanic friendly.

As early as the mid-20th century, metallurgists discovered the usefulness of sulfur in stainless steel. They found that sulfur formed compounds in stainlesssteel, which helped break stainless steel chips during machining and formed a lubricant layer on top of the cutting tools, reducing friction and extending tool life. The use of sulfur has been extended throughout the stainless steel industry, resulting in free machining grades such as 303, 416, and 420F.

Stainless steel is as common as aluminum in many stores, especially when manufacturing parts for the aerospace and automotive industries. It is a versatile material with many different alloys and grades that can be adapted to many applications.However, it is also one of the most difficult to process. Stainless steel is the infamous end mill assassin, so increasing speed and feed rates and choosing the right tools are critical to successful machining.

Material properties

Stainless steel is a high alloy steel with higher corrosion resistance than carbon steel and low alloy steel. This is mainly due to their high chromium content. Most grades of stainless steel alloys contain at least 10% of the elements.

Tool selection

When machining stainless steel, it is important to choose the right tool for your application. By choosing the right end mill style, you can optimize roughing,finishing, grooving, and efficient milling tool paths for stainless steel.

Traditional roughing

For traditional roughing, a 4- or 5-blade end mill is recommended. The 5-blade end mill has a higher feed rate than the 4-blade end mill, but both types of milling cutters are suitable for roughing.

Slotted

For slotted stainless steel, chip evacuation will be key. Therefore, 4 chip removal tools are the best choice, because the number of chip removal is small, and the chip removal can be more effective. Tools with chipbreaker geometries can also be efficiently grooved in stainless steel, as smaller chips are easier to eject from the cutting.

finishing

For best results when finishing stainless steel parts, high groove numbers and / orhigh helicity are required for best results. The finishing angle for stainless steel end mills will exceed 40 degrees and the number of grooves will be 5 ormore. For more aggressive finishing tool paths, the number of flutes can range from 7 flutes to as many as 14. Efficient milling With the right tools,high-efficiency milling can be a very effective stainless steel machining technology. The chip conveyor roughing machine will be an excellent choice for5 or 7-edged types, while standard 5-7-edged, variable pitch end mills willalso perform well in HEM tool paths.