GB/T 9439-88.The title is grey iron castings.Here are the some of the details:
1 The topic contents and scope of application
This standard stipulated the grey iron grades and the technical specification for castings.
This standard is applied to the grey iron castings cast by the sand moulds or the mould with a heat conductivity equivalent to sand mould. To the grey iron castings cast by other moulds, this standard may also
be applied as the reference.
2 Sources of standards
GB 5612 Expression for the grey iron grades
GB 6414 Dimensions tolerance of the castin
GB 6060.1 Reference specimen of surface roughness cast surface
GB 977 Testing method for mechanical property of grey iron castings
GB 223. 1-223.5 Chemical analysis method for steel and alloy
GB 7216Metallographic structure of grey iron
GB 5677 Classification on the radiograph and the grade of negative plate for the cast steel products
GB 7233 Ultrasonic detection and quality rating method for the cast steel products
GB 9444 Magnaflux inspection and quality rating method for the cast steel products.
3 Grey iron grades
1hc grades of this standard meet the stipulation of GR 5612. Based on the tensile strength of the singlecast test bar with diameter of 30 mm, grey iron is divided into six grades of 111 1(X). LIT 150, lIT 200. lIT 250, 1-IT 300 and UT 350.
4 Technical requirements
4.1 Manufacturing process and chemical composition
The manufacturing process and chemical composition for grey iron should be decided by supplier, however, the grey iron grates and respective index of mechanical propcrtics have to meet the stipulation of this standard.
If buyer has special requirement for the chemical composition of grey iron, should be arranged by both parties of buyer and supplier in the agreement of order.
4.2 Mechanical properties
4.2.1 Tcnsilc strength
4.2.1.1 Tensile strength of the singlcc.ast test bar
The tensile strength of grey iron in this standard based on the measure proceeded in a specimen machined from a singlecast lest bar should meet the stipulation of table 1.
4.2.1.2 Tensile strength of the cast on test bar(piece)
When the castings with a wall thickness over 20 mm and a weight over 200 kg, as well as with the special requirement, after making arrangement between both parties of buyer and supplier, the tensile strength may also be measured with the specimen machined from the cast on test bar(see Fig. 2)or cast on test piece(see Fig. 3)under the similar cooling conditions, the testing results should meet the stipulation of table 2, this ensile strength measured would be more closed to the material property of the castings itself than that from the singlecast test bar.
4.2.1.3 Tensile strength of castings with various wall thickness
The tensile strength of grey iron are related with the wall thickness of casting, different wall thickness section of the castings with same grey iron grade would bring different tensile strength. For the convenience of design and application, Table 3 provided the reference value of tensile strength can be reached by the grey iron castings with various grades and different wall thickness. If both parties of buyer and supplier agree and come to an arrangement, the material properties of castings may also be measured with the machined specimen cut off from the castings, and should meet the stipulation of table 3.