Description
SAE SPECIFICATIONS FOR CAST STEEL SHOT AND GRIT SCREENINGS
The following are paraphrased as condensations of the Society of Automotive Engineers (SAE) specifications and include all of the essential features of these specifications for:
- Cast Steel Shot — J827
- Cast Steel Grit — J1993
- Cast Steel Shot and Grit Sizes — J444
Chemical Analysis
- Carbon: .80 – 1.2%
Manganese:
- S-70 – S-110: .35 – 1.2%
- S-170: .50 – 1.2%
- S-230 & larger shot, all grit: .60 – 1.2%
- Silicon: .4% min
- Sulfur: .05% max
- Phosphorus: .05% max
ERVIN AMASTEEL® EXCEEDS ALL SAE SPECIFICATIONS
✔ Microstructure
The microstructure of cast steel shot and grit shall be uniform Martensite, tempered to a degree consistent with the hardness range, with fine well-distributed carbides, if any.
✔ Hardness
The hardness may be determined by any of the various methods applicable to small sections such as Micro Hardness Tester with a Knoop indenter, at loads determined to provide reliable conversion to Rockwell C.
Shot – Ninety percent of random hardness check performed on a representative sample shall fall within the range of 402–558 Knoop hardness number (40–51 HRC).
Grit – Ninety percent of random hardness check performed on a representative sample shall fall within the following ranges:
- S hardness range of 402–558 Knoop hardness number (40–51 HRC)
- M hardness range of 495–650 Knoop (47–56 HRC)
- L hardness range 612–754 Knoop (54–61 HRC)
- H hardness of 732 Knoop minimum (60 HRC)
✔ Density
The density of cast steel shall be not less than 7.3 gm/cc grit and 7 gm/cc for shot.
✔ General Appearance
The cast steel shot shall be as nearly spherical as commercially possible and no more than 20% of the shot particles shall have objectionable characteristics.
✔ Voids for Shot
No more than 10% of cast steel shot particles shall contain voids as determined at 10x magnification. A void must be greater than 10% of the area of the abrasive particle to be considered objectionable.
✔ Shrinkage
No more than 10% of cast steel shot particles shall contain shrinkage as determined at 10x magnification. Shrinkage is an internal cavity with irregular dendritic surfaces, whose area is larger than 40% of the particle area.
✔ Cracks
No more than 15% of cast steel shot and 40% of the cast steel grit particles shall have cracks as determined at 10x magnification. A crack is a linear discontinuity whose length is greater than 3x its width and radial in direction.
✔ Particle Shape of Shot
When examined at 10x magnification, no more than 5% of the shot particles will have a length that is in excess of twice the cross section.
✔ Mechanical Tests
See SAE J445 for methods of checking uniformity of shipments of shot or grit to determine relative fatigue life and energy transfer of different types of shot or grit.
ERVIN AMASTEEL® Special Hardness
- M hardness – 90% min 495–650 KHN (47–56 HRC)
- L hardness – 90% min 612–754 KHN (54–61 HRC)
- H hardness – 90% min 732 KHN (60 HRC min)
AMASTEEL is also available in other hardness ranges.
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