January/February 1988
What Grade of Stainless Is It?
Series No. 1
Are you selling stainless steel without determining the grade alloy of your material? If so, you may not be getting the best possible price for your product-higher grade alloys command higher prices. Spark testing stainless steel to determine the alloy can help you set your prices appropriately.
This Scrap Processing and Recycling series illustrates the characteristics of the spark emitted during testing of stainless steel. In addition to using this series as a reference, you can use a set of posters available from ISRI. The three full-color, 24-inch by 36-inch posters illustrate test sparks for the following stainless steel alloys: 301, 304, 316, and 321; 309 (25/12) and 310 (25/20); and high-speed steel TI, T5, T15, Ml, and M2.
The posters are printed on long-lasting, plastic-coated paper and are suitable for hanging in your shop. To order a set ($20 per set), contact ReMA at 202/466-4050; 1627 K Street, N.W, Suite 700, Washington, DC 20006.
Stainless Steel 301
301 spark similar to 304. Bright yellow spark pattern appears immediately, 6-10 inches long, many carrier lines.
1. Star bursts and crows feet at ends of carrier lines.
2. Some spear points.
3. Spark travels completely around wheel with bright glow.
4. Spark stream leaves wheel at smaller angle than 304.
Since 301 and 304 are similar, compare both sparks for differences. 301 is longer, lighter in color, and has more crows feet at end of carrier lines.
Note: Short, steady, red spark, with different characteristics than described on chart, may indicate higher grade alloy. Hold aside for further testing.
Stainless Steel 304
304 spark similar to 301. Spark pattern appears immediately, is bright yellow (but darker than 301) and 6-8 inches long (shorter than 301) with many straight carrier lines.
1. Spear points at end of carrier lines.
2. Spark travels completely around wheel with very bright glow.
3. Sparks leave wheel at large angle.
Since 304 and 301 are similar, compare both sparks for differences. 304 is shorter and darker in color.
Note: Short, steady, red spark, with different characteristics than described on chart, may indicate higher grade alloy. Hold aside for further testing.
Are you selling stainless steel without determining the grade alloy of your material? If so, you may not be getting the best possible price for your product-higher grade alloys command higher prices. Spark testing stainless steel to determine the alloy can help you set your prices appropriately.