Some customers ask Dandong Iron Casting Group how about the rough casting tolerance standard of iron castings and steel castings, Our experience is to use the international tolerance standard ISO8062 to determine the casting tolerance range expect customer specified.

It mainly indicate the tolerance of castings, such as sand casting, investment casting and other casting method. It Applies to cast metals and their alloys produced by various casting manufacturing processes. Is applicable both to general tolerances and/or required machining allowances given on a drawing and to individual tolerances and/or required machining allowances which are shown immediately following a specific dimension. The system specified applies when the foundry provides the pattern or die equipment or accepts responsibility for proving it.

 

Raw casting basic dimension mm		Total casting tolerance mm
over	up to and include	Casting tolerance grade CT
		1	2	3	4	五	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	五 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	五 5.6 6.2	7 8 9	10 11 12	12 14 16	16 18 20	20 22 25
400 630 1 000	630 1 000 1 600	– – –	– – –	– – –	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	五 6 7	7 8 9	10 11 13	14 16 18	18 20 23	22 25 29	28 32 37
1 600 2 500 4 000 6 300	2 500 4 000 6 300 10 000	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	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 三十 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.

From the standard you can find investment casting is CT5~CT7; sand casting is CT8~CT10; shell mould casting is CT8; automatic machine casting is CT9; resin sand casting is CT9~CT10; green sand casting is CT10~CT12.

This standard is a universal tolerance requirement. The casting size deviation is related to many factors, such as compactness of sand, sand strength, liquid iron temperature, air humidity, chemical composition, moisture content of sand grains and workers’ operation.

Dandong Iron Casting Group has been strict in accordance with ISO8062 standards to control casting tolerance, the unqualified products will be melted down as waste product.