GB/T 26653-2026Exhaust manifold castings (English PDF)

5.1 Chemical composition

5.1.1 The chemical composition of cast iron parts of grades HT200, HT250, RuT300, QT400-15, QT400-18, and QT450-10 shall not be used for acceptance. According to the regulations, the chemical composition of other grades of cast iron parts should conform to the provisions of Table 1.

5.1.2 The chemical composition of cast steel parts shall conform to the provisions of Table 2.

5.2 Mechanical Properties The mechanical properties of the castings shall conform to the specifications in Table 3.

5.3 Metallographic Structure

5.3.1 The metallographic structure of cast iron parts shall conform to the specifications in Table

4.When there are special requirements, the purchaser shall specify them in the product drawings or supply contract. The metallographic structure of cast steel parts shall not be used as a basis for acceptance.

5.3.2 Castings may be supplied in the as-cast condition. Heat treatment is permitted to achieve the required mechanical properties and metallographic structure.

5.4 Geometric shape and dimensional tolerances The geometry and dimensions of castings shall conform to the specifications in the drawings or relevant technical requirements. Unless otherwise specified, the dimensional tolerances of castings shall be... The grade should meet the requirements of DCTG8 in GB/T 42124.3-2025, and the geometric tolerance grade should conform to GB/T 42124.3-2025. According to the GCTG6 standard, misalignment should not affect processing or installation, and the wall thickness after misalignment should not be less than the minimum allowable wall thickness.

5.5 Surface Quality

5.5.1 Castings shall be thoroughly cleaned. The removal of gating and riser residues, scale, burrs, etc., shall conform to the drawings or the order between the supplier and the buyer. agreement.

5.5.2 The surface roughness of the inner and outer surfaces of the casting shall be determined according to the requirements of the buyer's drawings. If the drawings do not specify, the roughness shall be selected in accordance with the provisions of GB/T 6060.1.

5.5.3 Castings shall be shot blasted to remove adhering sand, oxide scale, etc.

5.6 Internal Quality

5.6.1 Casting defects are not allowed in castings. Casting defects that are not allowed in castings include.

a) Castings shall not have casting defects (such as cracks, cold shuts, shrinkage cavities, inclusions, etc.) that affect the performance of the casting.

b) The inner cavity of the casting shall not have burrs, scales, or other casting defects that affect the venting state.

c) No casting defects of any size are allowed to be present simultaneously on the same part of the inner and outer surfaces of the casting pipe wall.

5.6.2 Permissible casting defects in castings Without affecting performance, the following casting defects are permissible in castings.

a) Casting defects less than one-fifth of the total depth of the bolt holes are permitted at the bolt hole location of the casting, and the casting defect should be within a certain distance from the end face of the threaded hole. The thread pitch should be no less than 3, and the defect should not affect the installation or the strength after installation.

b) Slight shrinkage porosity is permissible at hot spots in castings. The shrinkage porosity should not exceed one-fifth of the cross-section of the affected area, and the distance from the affected area to... The thickness of the inner wall is not less than the thickness of the pipe wall, and it does not affect machining, nor reduce the strength and installation performance of the casting.

c) Castings are permitted to contain casting defects that can be removed by machining.

d) The types, quantities, and ranges of permissible casting defects on non-machined surfaces and inside castings shall conform to the requirements of the buyer's drawings and technical specifications. The stipulations of the supply agreement between the demanding and the supplying parties.

e) Casting defects that do not affect performance can be repaired.

5.7 Cleanliness The cleanliness of the castings should meet the requirements of the drawings.

5.8 Air tightness Castings should undergo an airtightness test after machining, according to the drawings or product technical requirements.

5.9 Weight Tolerance The weight tolerance of castings shall conform to the specifications in the drawings or relevant technical requirements. Unless otherwise specified, the weight tolerance grade of castings shall conform to... The MT8 grade specification in GB/T 11351-2017.

6.1 Chemical Composition Analysis

6.1.1 Chemical composition analysis methods may include chemical analysis and spectroscopic analysis; the specific method shall be determined through negotiation between the supplier and the buyer. When analyzing... When there is a dispute over the results, chemical analysis shall be used for arbitration.

6.1.2 Sampling methods for chemical analysis shall be performed in accordance with GB/T 20066, and sampling methods for spectroscopic analysis shall be performed in accordance with GB/T 5678.

6.1.3 When using chemical analysis methods, follow GB/T 223.3, GB/T 223.4, GB/T 223.5, GB/T 223.11, GB/T 223.12, GB/T 223.23, GB/T 223.25, GB/T 223.26, GB/T 223.38, GB/T 223.40, GB/T 223.58, GB/T 223.60, The requirements of GB/T 223.64, GB/T 223.68, and GB/T 223.71 shall apply. When using spectral analysis, GB/T 14203 and GB/T 223.71 shall apply. The provisions of GB/T 11170 shall apply.

6.2 Mechanical property test

6.2.1 The room temperature mechanical property test of the material shall be carried out in accordance with the provisions of GB/T 228.1.

6.2.2 The hardness test site is the mating surface between the casting and the cylinder head. The hardness test method shall be performed in accordance with GB/T 231.1.

6.3 Metallographic Structure Examination Metallographic inspection of gray cast iron parts shall be performed in accordance with GB/T 7216, and metallographic inspection of vermicular graphite cast iron parts shall be performed in accordance with GB/T 26656. Okay, the metallographic inspection of ductile iron parts shall be carried out in accordance with the provisions of GB/T 9441.

6.4 Geometric shape and dimensional inspection

6.4.1 The wall thickness of the casting can be measured by methods such as dissection, thickness calipers or 3D scanning.

6.4.2 The casting misalignment value is measured by scribing or 3D scanning.

6.5 Surface quality inspection

6.5.1 Visible defects on the surface of castings shall be inspected on a piece-by-piece basis by visual inspection.

6.5.2 Surface defects that are not visible on castings can be inspected using magnetic particle testing or penetrant testing methods. Magnetic particle testing shall be conducted in accordance with GB/T 9444. The penetration test shall be performed in accordance with the provisions of GB/T 9443.

6.5.3 The surface roughness of the casting shall be tested in accordance with the provisions of GB/T 15056.

6.6 Internal Quality Inspection Internal defects in castings can be inspected using X-rays, ultrasonic waves, etc., with specific methods conforming to the provisions of GB/T 5677 and GB/T 34904. implement.

6.7 Cleanliness Test The cleanliness test shall be performed in accordance with the provisions of GB/T 3821.

6.8 Air tightness test

6.8.1 The airtightness test of castings shall be conducted using either the wet leak test method or the dry leak test method.

6.8.2 During the airtightness test, the test process parameters should be formulated according to the requirements of the customer for different products and specifications.

6.9 Weight Inspection The inspection of casting weight deviation shall be carried out in accordance with the provisions of GB/T 11351-2017.

7.2 Composition and Inspection Quantity of Sampling Batches

7.2.1 Composition of Sampling Batches Inspection batches are classified as follows:

a) Castings poured from the same ladle of molten iron constitute a batch and form a sampling batch.

b) In continuous production, each sampling batch consists of castings with a maximum weight of.2000 kg or cast in 2 hours, constituting one sampling batch. Both the supplier and the buyer agree that the batch of samples can be changed.

c) If, within a certain time interval, a change occurs in the production process (change in furnace charge, change in process conditions, or change in required chemical composition), When there are changes, all castings poured from the continuously molten iron during this period, regardless of how short the time interval, are considered as one sample. batch.

d) Except as provided in a), upon agreement between the supplier and the buyer, several batches of castings may be combined into one group for acceptance. In this case, the supplier... The production process should have continuous testing methods, such as pre-furnace metallographic inspection and spectral analysis, and these methods should be able to prove that the production process is stable. The molten iron is standardized and meets the requirements; each batch of processed molten iron has a test record and is traceable.

e) Each heat treatment of castings is considered as a sampling batch, or castings with the same structure in each heat are considered as a single sample. batch.

7.2.2 Number of batches tested Each sampled batch must be inspected unless the quality control system in the production process combines sampled batches and takes pre-emptive safeguards. The sampling batch and the number of tests should be agreed upon by both the supplier and the buyer when the order is accepted.

7.3 Validity of the experiment

7.3.1 If the mechanical property test results do not meet the requirements due to any of the following reasons, rather than a quality problem with the casting itself. If the time is not met, the experiment is invalid.

a) Improper mounting of the tensile specimen on the testing machine or improper operation of the testing machine.

b) The tensile specimen has casting defects or improper cutting and machining.

c) The tensile specimen breaks outside the gauge length.

d) Casting defects were found at the fracture surface of the tensile specimen after tensile testing.

7.3.2 In the above circumstances, samples should be taken again from the same test block or from test blocks cast in the same batch for retesting. The results replace the results of invalid experiments.

7.3.3 The results of the retest shall be taken as the final test results.

7.4 Judgment Rules The rules for judging the test results are shown in Table 6.

8.3 Packaging, storage and transportation

8.3.1 After the castings pass inspection, the methods of rust prevention, packaging and storage shall be agreed upon by the supplier and the buyer.

8.3.2 For castings transported over long distances, the packaging and transportation methods shall be agreed upon by both the supplier and the buyer in accordance with the provisions of the transportation regulations. GB/T 26653-2026. Exhaust Manifold Castings ICS

31 National Standards of the People's Republic of China Replaces GB/T 26653-2011 Exhaust manifold casting Published on 2026-02-

27 Implemented on 2026-09-

01 State Administration for Market Regulation The State Administration for Standardization issued a statement.