GB/T 13820-2018Magnesium alloy castings (English PDF)

Foreword

This Standard is drafted in accordance with stipulations in GB/T 1.1-2009. This Standard serves as a replacement of GB/T 13820-1992 Magnesium Alloy Castings. In comparison with GB/T 13820-1992, there are several main technical changes as follows:

---The location of taking test pieces from castings is modified (please refer to 6.3.2.1;

6.3.1 in Version 1992);

---The requirements of mechanical properties of partial alloy body or attached casting sample are added (please refer to 4.3.1);

---The requirements of inclusion test of casting flux are added (please refer to 4.5.3);

---It is also added that segregation inhomogeneity that exists in the form of lines, streamlines and dots is allowed on the surface of magnesium alloy castings that contain zirconium (please refer to 4.5.8);

---The test methods of chemical composition of castings are modified (please refer to 5.1;

5.1 in Version 1992);

---The stipulations of batch are modified (please refer to 6.1;

6.1 in Version 1992);

---The test items of various castings are added (please refer to 6.2);

---Determination and re-inspection are added (please refer to 6.4);

---The requirements of re-sampling for analysis when alloys are unqualified in chemical composition are modified (please refer to 5.1.2;

6.2.4 in Version 1992);

1 Scope

GB/T 13820-2018 is the Chinese national standard for magnesium alloy castings produced by sand casting and metal mould casting. It fixes the classification of the castings, the technical requirements, the test methods, the inspection rules and the marking, packaging, transport and storage. Castings are sorted into classes by the severity of service, and for each class the standard sets what has to be verified: chemical composition, mechanical properties measured on separately cast or attached test bars, internal soundness, surface condition and dimensional conformity. This third edition replaces GB/T 13820-1992 and changes the substance in several places - it moves where the test piece is taken from the casting, adds mechanical property requirements for the alloy body and for attached cast samples, adds an inclusion test for the casting flux, allows the line, streamline and dot segregation that appears on zirconium-bearing magnesium castings, revises the chemical analysis methods and the definition of a batch, adds the test items per casting class together with determination and re-inspection, and deletes the routine inspection of the 1992 edition. Annex A shows how internal defects are read on an X-ray film.

This Standard specifies the classification, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of magnesium alloy castings (hereinafter referred to as "castings"). This Standard is applicable to magnesium alloy castings that are manufactured with sand casting and metal casting.

2 Normative References

The following documents are indispensable to the application of this Standard. In terms of references with a specified date, only versions with a specified date are applicable to this Standard. The latest version (including all the modifications) of references without a specified date is also applicable to this Standard.

GB/T 228.1 Metallic Materials - Tensile Testing - Part 1. Method of Test at Room Temperature

GB/T 1177-2018 Casting Magnesium Alloys

GB/T 6414 Castings - Dimensional Tolerances and Geometrical Tolerances and Machining Allowances

GB/T 11351 Mass Tolerances of Casting

GB/T 13748.1 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 1. Determination of Aluminum Content

GB/T 13748.4 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 4. Determination of Manganese Content - Periodate Spectrophotometric Method

GB/T 13748.6 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Determination of Silver Content - Determination of Silver Content - Flame Atomic Absorption Spectrophotometric Method

GB/T 13748.7 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 7. Determination of Zirconium Content

GB/T 13748.8 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 8. Determination of Rare Earth Content - Gravimetric Method

GB/T 13748.9 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 9. Determination of Iron Content - O-phenanthroline Spectrophotometric Method

GB/T 13748.10 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 9. Determination of Silicon Content - Molybdenum Blue Spectrophotometric Method

GB/T 13748.11 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Determination of Beryllium Content - Solochrome Cyanine R Spectrophotometric Method

GB/T 13748.12 Chemical Analysis Methods of Magnesium and Magnesium Alloys - Part 12. Determination of Copper Content

4 Technical Requirements...

5 Test Methods...

6 Inspection Rules

6.1 Group Batch Castings that are poured in the same smelting furnace within 8 h and adopt the same thermal treatment process shall be deemed as one batch. Under special circumstances, batch shall be negotiated and determined by the demand side and the supply side.

6.2 Test Items Castings shall be tested in accordance with the category. Please refer to Table 6 for the test items of various castings.

6.4.1 Chemical composition When castings are submitted for the analysis of chemical composition for the first time and are deemed as unqualified, it is allowable to re-sample for the analysis of unqualified elements. If they still fail in the second analysis, this smelting furnace of castings shall be determined as unqualified in chemical composition.