High silicon corrosion resistant cast iron of valve material

High silicon corrosion resistant cast iron of valve material

This standard specifies the technical requirements, test methods, sampling and inspection rules, casting marking, packaging, storage and transportation requirements for high silicon corrosion resistant cast iron. This standard is applicable to high silicon corrosion resistant cast iron with silicon content of 10, 00%~15. 00%. Drawings indicating specifications, shapes and dimensions, instructions for casting cleaning, drawings indicating key dimensions and giving all dimensional tolerances. If the demander provides the model, the size of the casting shall be in accordance with the size reserved for the model. Whether a hydraulic test is required, and if so, the test pressure and allowable leakage should be indicated.
range
This standard specifies the technical requirements, test methods, sampling and inspection rules, casting marking, packaging, storage and transportation requirements for high silicon corrosion resistant cast iron. This standard is applicable to high silicon corrosion resistant cast iron with silicon content of 10, 00%~15. 00%.
Normative reference document
The terms in the following documents become terms of this Standard by reference to this Standard. For dated citations, all subsequent amendments (excluding erratum) or amendments are not applicable to this Standard; however, parties to an agreement under this Standard are encouraged to investigate the availability of *** versions of these documents. For undated references, their versions are applicable to this standard.
Order information
The following order information shall be provided by the demander:
a) The standard number of execution.
b) high silicon cast iron brand.
c) Number of castings.
d) Casting weight.
e) Drawings indicating specifications, shapes and dimensions, instructions for casting cleaning, drawings indicating key dimensions and giving all dimensional tolerances. If the demander provides the model, the size of the casting shall be in accordance with the size reserved for the model.
Options in order information:
a) The heat treatment status of the casting at the time of delivery;
b) Whether to provide the demander with the chemical composition analysis report;
c) Whether a bending test is required;
d) Whether a hydraulic test is required, and if so, the test pressure and allowable leakage should be indicated.
e) Any special packaging, marking, etc.
Production method
Unless otherwise specified, the melting method and casting process shall be determined by the Supplier.
Technical requirement
Grade and chemical composition of high silicon corrosion resistant cast iron
The grade expression method of high silicon corrosion resistant cast iron conforms to the provisions of GB/T 5612, which is divided into four grades.
High silicon corrosion resistant cast iron grade and corresponding chemical composition see
The acceptance of high silicon corrosion resistant cast iron shall be based on its chemical composition, which shall comply with the provisions of Table 1.
Mechanical property
The mechanical properties of high silicon corrosion resistant cast iron are generally not taken as the basis for acceptance. If required by the demander, the test rod shall be subjected to a bending test to determine its bending strength and deflection, and the test results shall comply with the provisions of Table 2.
(2) High silicon corrosion resistant cast iron is a kind of brittle metal material, in the structural design of its castings should not be sharp and sharp cross section transition. The geometry and size of the castings shall conform to the drawing or technical requirements of the demander. If the Demander has no special requirements on the dimensional tolerance of the casting, the relevant provisions of GB/T 6414 shall be followed. Castings should be cleaned up, trimmed more “flesh”, remove pouring riser, core bone, clay sand and inner cavity residue, etc. The residual of pouring riser, covering seam, flying spike and inner cavity cleanliness of castings shall conform to the drawing or technical requirements of the buyer or the order agreement between the two parties.
Top up: high silicon corrosion resistant cast iron of valve material (I)
Test rod
The bending test of high silicon corrosion resistant cast iron adopts a single test bar with diameter of 30mm and length of 330mm without mechanical machining. Its specifications are shown in Figure 1.
Unit: millimeter
Note: The recommended casting size of the test bar should be cooled to 540℃ in the mold before sand fall, and the residual stress should be removed before the bending test.
The single casting test rod shall be poured in the same batch of liquid iron as the casting (primary and final packages shall not be used). In the same casting mold, multiple test rods can be poured at the same time, and the reference process is shown in Figure 2.
Unit: millimeter
Geometric and dimensional tolerances
High silicon corrosion resistant cast iron is a kind of brittle metal material, and sharp cross section transition should not be required in the structural design of its castings. The geometry and size of the castings shall conform to the drawing or technical requirements of the demander. If the Demander has no special requirements on the dimensional tolerance of the casting, the relevant provisions of GB/T 6414 shall be followed.
Weight deviation
If there is no special requirement for casting weight deviation, the relevant provisions of GB/T 11351 shall be followed.
Surface quality
The surface roughness of castings shall conform to GB/T 6061.1 or demander’s drawings or technical requirements.
Castings should be cleaned up, trimmed more “flesh”, remove pouring riser, core bone, clay sand and inner cavity residue, etc. The residual of pouring riser, covering seam, flying spike and inner cavity cleanliness of castings shall conform to the drawing or technical requirements of the buyer or the order agreement between the two parties.
Casting defect
There shall be no casting defects that reduce the strength and damage the appearance of the product. The allowable defects and the dressing method shall be agreed by the parties.
Heat treatment
High silicon cast iron is usually applied in heat treatment state (to remove residual stress). For small castings of simple shape, if they are supplied as cast, both parties must agree.
Castings shall undergo heat treatment to remove residual stress. If the demander has no special requirements, the casting can be carried out in the following ways:
Casting sand drop in red hot state, quickly eliminate all mechanical resistance to free shrinkage of casting, eliminate casting risers, red hot casting directly into the heat treatment furnace preheating higher than 600℃, then slowly heating, relatively low insulation temperature of 870℃. At a temperature higher than 870℃, according to the relatively large wall thickness of the castings, the time of insulation should be 1.h/ 25mm, but the minimum insulation time should not be less than 2h. Then it is cooled at a speed of no more than 55℃/15 min. It is cooled to 205℃ with the furnace and air cooled at normal temperature.
Special requirement
If the demander has requirements for magnetic particle testing, ultrasonic testing, X-ray testing, etc., the demander and the demander shall negotiate and execute according to the provisions of GB/T 9444, GB/T 7233 and GB/T 5677 respectively.
Test method
Chemical analysis
Conventional, spectral or other instrumental methods are acceptable but should be standardized to produce the same results.
Conventional sampling methods for chemical analysis shall be carried out according to GB/T 20066.
The arbitrated analysis of carbon, silicon, manganese, sulfur and phosphorus in the chemical composition was calculated according to GB/T 20123 or GB/T 223.69,GB/T 223.60,
GB/T 223. 58 or GB/T 223. 64,GB/T 223. 3 or GB/T 223. 59 or GB/T 223. 61,GB/T 223. 53 Chrome, key, copper arbitration analysis shall be performed in accordance with GB/T 223.11 or GB/T 223.12,GB/T 223.26,GB/T 223.18 or GB/T 223.19 or GB/T 223.53, respectively.
The spectral sampling method is performed according to GB/T 5678 and GB/T 14203. The spectral analysis method shall be carried out according to GB/T 20125.