What standard can be used for the rough casting tolerance for iron and steel materials? How to choose suitable casting process for your iron and steel castings? Which casting process is suitable to your products?
After years experience, we found many standards can help you to solve these questions. Please check the following table, you will find what tolerance grade can be reached by every casting process. We have referred to the standards of ISO 8062:1994, SFSA200 and BS6615:1996. and we hope these information will be helpful for you to choose a suitable casting process.
As for the imperial (inch) tolerance standard, please check our article Rough Casting Tolerance by Inch.
Reachable Casting Tolerance Grades of Casting Processes
Conditions, Casting Processes |
Select Tolerance Grades |
all sand molding process fully capable including hand molding, most appropriate for large castings | CT 12-14 |
appropriate for most casting types and sand molding processes | CT 10-12 |
Sand castings made by automatic moulding, molding machine and shell molding process. | CT 8-10 |
permanent metal moulding process and low pressure casting. | CT 7-9 |
lost wax investment casting process include water glass and silicon. Silicon is better than water glass. | CT 5-7 |
BS 6615 : 1996 – Rough Casting Tolerances
Raw casting |
Total casting tolerance |
||||||||||||||||
over | up to and including |
Casting tolerance grade (CT) |
|||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | ||
– 10 16 |
10 16 25 |
0.09 0.1 0.11 |
0.13 0.14 0.15 |
0.18 0.2 0.22 |
0.26 0.28 0.3 |
0.36 0.38 0.42 |
0.52 0.54 0.58 |
0.74 0.78 0.82 |
1 1.1 1.2 |
1.5 1.6 1.7 |
2 2.2 2.4 |
2.8 3 3.2 |
4.2 4.4 4.6 |
– – 6 |
– – 8 |
– – 10 |
– – 12 |
25 40 63 |
40 63 100 |
0.12 0.13 0.14 |
0.17 0.18 0.2 |
0.24 0.26 0.28 |
0.32 0.36 0.4 |
0.46 0.5 0.56 |
0.64 0.7 0.78 |
0.9 1 1.1 |
1.3 1.4 1.6 |
1.8 2 2.2 |
2.6 2.8 3.2 |
3.6 4 4.4 |
5 5.6 6 |
7 8 9 |
9 10 11 |
11 12 14 |
14 16 18 |
100 160 250 |
160 250 400 |
0.15 – – |
0.22 0.24 – |
0.3 0.34 0.4 |
0.44 0.5 0.56 |
0.62 0.7 0.78 |
0.88 1 1.1 |
1.2 1.4 1.6 |
1.8 2 2.2 |
2.5 2.8 3.2 |
3.6 4 4.4 |
5 5.6 6.2 |
7 8 9 |
10 11 12 |
12 14 16 |
16 18 20 |
20 22 25 |
400 630 1000 |
630 1000 1600 |
– – – |
– – – |
– – – |
0.64 – – |
0.9 1 – |
1.2 1.4 1.6 |
1.8 2 2.2 |
2.6 2.8 3.2 |
3.6 4 4.6 |
5 6 7 |
7 8 9 |
10 11 13 |
14 16 18 |
18 20 23 |
22 25 29 |
28 32 37 |
1600 2500 4000 300 |
2500 4000 6300 10000 |
– – – – |
– – – – |
– – – – |
– – – – |
– – – – |
– – – – |
2.6 – – – |
3.8 4.4 – – |
5.4 6.2 7 – |
8 9 10 11 |
10 12 14 16 |
15 17 20 23 |
21 24 28 32 |
26 30 35 40 |
33 38 44 50 |
42 49 56 64 |
For sizes up to 16 mm, general tolerances form CT 13 to CT16 are not available. For these sizes individual tolerances shall be indicated. Grade 16 exists only for wall thicknesses of castings generally specified to CT15. |