Casting shape and size inspection is to check whether the actual size of the blank casting falls within the specified size tolerance band of the blank casting.
According to general regulations, the shape and position errors of castings should be within the relevant size tolerance range.
Inspection of casting shape
The basic elements of casting shape mainly include straightness, flatness, roundness, cylindricity, line profile, surface profile, parallelism, verticality, inclination, position, concentricity (to the center point), coaxiality (to the axis), symmetry, etc.
Usually, castings with low precision requirements do not check geometric errors. However, for castings with geometric error requirements, this inspection is required, because the geometric error of castings always exists objectively, and we cannot make castings without any geometric error, but can only limit the geometric error within the permitted range.
Inspection of casting size
Usually, there are several situations where the casting size needs to be inspected:
According to the casting drawing or casting process document, all dimensions of the casting need to be inspected. It often appears in the first trial production casting or the random sampling casting size inspection during batch production, or the castings produced in small batches.
According to the casting drawing or casting process document, several control dimensions of the casting need to be inspected, that is, the dimensions with high precision requirements or the dimensions that are easy to deform or the dimensions that can represent the degree of deformation of the casting. It is often used for controlled inspection of the casting dimensions produced in large quantities on the assembly line.
According to arbitration inspection, the controversial casting dimensions in the machining process need to be analyzed.
| Raw casting basic dimension (mm) |
General Casting Tolerance in mm | |||||||||||||||||
| ＞ | ≤ | 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 6300 |
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 |
|
| The dimension tolerances for lost wax investment casting of water glass processed are according CT7. | ||||||||||||||||||
| Table—Tolerance grades for long-series production raw castings | ||||||||||
| Method | Tolerance grade CT | |||||||||
| Casting material | ||||||||||
| Steel | Grey iron | S.G.iron | Malleable iron |
Copper alloys |
Zinc alloys |
Lightmetal alloys |
Nicked based alloys |
Cobalt based alloys |
||
| Sand cast, hand-moulded |
11-14 | 11-14 | 11-14 | 11-14 | 10-13 | 10-13 | 9-12 | 11-14 | 11-14 | |
| Sand cast, machine-moulded and shell moulding |
8-12 | 8-12 | 8-12 | 8-12 | 8-10 | 8-10 | 7-9 | 8-12 | 8-12 | |
| Metallic permanent mould (gravity and low-pressure) |
- | 8-10 | 8-10 | 8-10 | 8-10 | 7-9 | 7-9 | - | - | |
| Pressure die casting |
- | - | - | - | 6-8 | 4-6 | 4-7 | - | - | |
| Investment casting |
water glass | 7-9 | 7-9 | 7-9 | - | 5-8 | - | 5-8 | 7-9 | 7-9 |
| silica sol | 4-6 | 4-6 | 4-6 | - | 4-6 | - | 4-6 | 4-6 | 4-6 | |
| NOTES 1 The tolerance grades indicated are those which can normally be held for castings produced in long series and when production factors influencing the dimensional accuracy of the casting have been fully developed. 2 This International Standard can also be applied to processes and materials not cited in this table by agreement between the producer and the user of the castings. |
||||||||||
| Table—Tolerance grades for short-series or single-production raw castings | |||||||||
| Method | Moulding material |
Tolerance grade CT | |||||||
| casting material | |||||||||
| Steel | Grey iron | S.G.iron | Malleable iron |
Copper alloys |
Light metal alloys | Nickel based alloys |
Cobalt based alloys |
||
| Sand cast, hand-moulded |
Clay- bonded |
13-15 | 13-15 | 13-15 | 13-15 | 13-15 | 11-13 | 13-15 | 13-15 |
| Chemically bonded |
12-14 | 11-13 | 11-13 | 11-13 | 10-12 | 10-12 | 12-14 | 12-14 | |
| NOTES 1 The tolerance grades indicated are those which can normally be held for sand castings produced in short series or as single castings. 2 The values in this table apply generally to basic dimensions greater than 25 mm.For smaller dimensions,finer tolerances can normally be economically and practically held as follows: a)basic dimension up to 10 mm:three grades finer; b)basic dimension 10 mm to 16mm:two grades finer; c)basic dimension 16 mm to 25 mm:one grade finer. 3 This International Standard can also be applied to processes and materials not cited in this table by agreement between the producer and the user of the castings. |
|||||||||
|
Largest dimension mm |
Required machining allowance mm |
||||||||||
|
Required machining allowance grade |
|||||||||||
|
＞ |
≤ |
A |
B |
C |
D |
E |
F |
G |
H |
J |
K |
|
- |
40 |
0.1 |
0.1 |
0.2 |
0.3 |
0.4 |
0.5 |
0.5 |
0.7 |
1 |
1.4 |
|
40 |
63 |
0.1 |
0.2 |
0.3 |
0.3 |
0.4 |
0.5 |
0.7 |
1 |
1.4 |
2 |
|
63 |
100 |
0.2 |
0.3 |
0.4 |
0.5 |
0.7 |
1 |
1.4 |
2 |
2.8 |
4 |
|
100 |
160 |
0.3 |
0.4 |
0.5 |
0.8 |
1.1 |
1.5 |
2.2 |
3 |
4 |
6 |
|
160 |
250 |
0.3 |
0.5 |
0.7 |
1 |
1.4 |
2 |
2.8 |
4 |
5.5 |
8 |
|
250 |
400 |
0.4 |
0.7 |
0.9 |
1.3 |
1.8 |
2.5 |
3.5 |
5 |
7 |
10 |
|
400 |
630 |
0.5 |
0.8 |
1.1 |
1.5 |
2.2 |
3 |
4 |
6 |
9 |
12 |
|
630 |
1000 |
0.6 |
0.9 |
1.2 |
1.8 |
2.5 |
3.5 |
5 |
7 |
10 |
14 |
|
1000 |
1600 |
0.7 |
1 |
1.4 |
2 |
2.8 |
4 |
5.5 |
8 |
11 |
16 |
|
1600 |
2500 |
0.8 |
1.1 |
1.6 |
2.2 |
3.2 |
4.5 |
6 |
9 |
13 |
18 |
|
2500 |
4000 |
0.9 |
1.3 |
1.8 |
2.5 |
3.5 |
5 |
7 |
10 |
14 |
20 |
|
4000 |
6300 |
1 |
1.4 |
2 |
2.8 |
4 |
5.5 |
8 |
11 |
16 |
22 |
|
6300 |
10000 |
1.1 |
1.5 |
2.2 |
3 |
4.5 |
6 |
9 |
12 |
17 |
24 |
| 1)Largest overall dimension of the casting,after final machining.
2)Grades A and B shall only be applied in special cases,for example with series production in which the pattern equipment,the casting procedure and the machining procedure with regard to clamping surfaces and datum surfaces or targets have been agreed between the customer and the foundry. |
|||||||||||
| Table—Typical required machining allowance grades for raw castings | |||||||||
| Method | Required machining allowance grade | ||||||||
| Casting material | |||||||||
| Steel | Grey iron | S.G.iron | Malleable iron |
Copper alloys |
Zinc alloys | Lightmetal alloys |
Nicked based alloys |
Cobalt based alloys |
|
| Sand cast, hand-moulded |
G-K | F-H | F-H | F-H | F-H | F-H | F-H | G-K | G-K |
| Sand cast machine-moulded,and shell moulding | F-H | E-G | E-G | E-G | E-G | E-G | E-G | F-H | F-H |
| Metallic permanent mould(gravity and low-pressure) |
- | D-F | D-F | D-F | D-F | D-F | D-F | - | - |
| Pressure die casting | - | - | - | - | B-D | B-D | B-D | - | - |
| Investment casting | E | E | E | - | E | - | E | E | E |
| NOTES This International Standard can also be applied to processes and materials not given in this table by agreement between the producer and the user of the castings. |
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Post time: Jun-19-2025