1. Chemical composition and mechanical properties of product materials
| C | Si | Mn | P | S |
| 0.17~0.25 | ≤0.60 | 0.8-1.2 | ≤0.025 | ≤0.025 |
| Ni | Cr | Cu | Mo | V | Total |
| 0.40 | 0.35 | 0.40 | 0.15 | 0.05 | 1 |
The material used for the splay saddle head steel casting is ZG270-480H. The chemical composition and mechanical properties must comply with the provisions of the standard Steel Castings for Welded Structures (GB/T 7659-2010). The heat treatment state is: annealing+normalizing+tempering. See Table 1 and Table 2 for details
| Yield strength/MPa | Tensile strength/MPa | Elongation after fracture/% | Reduction of area/% | Impact absorbing energy Akv/J | Impact absorbing energy Aku/J |
| ≥270 | ≥480 | ≥20 | ≥35 | ≥40 | / |
2. Technical quality requirements for splay saddle head
1) The product shall control the machining allowance of the machined surface and the size of the non machined surface according to the drawing requirements. The machined surface shall be subject to ultrasonic flaw detection in accordance with GB/T7233.1-2009, and 100% of the machined surface shall be qualified as Grade III. After sand cleaning, the steel castings shall be annealed as a whole, and normalized and tempered after the riser is cut, the shape is rough, or the welding is repaired. The edges and corners of the steel castings shall be polished and then subject to magnetic particle flaw detection according to GB/T9444-2007, which is qualified as Grade II. After rough machining of the machined surface of the steel casting, at least 10 mm of machining amount shall be reserved. Penetrant flaw detection shall be carried out according to GB/T9443-2007, among which: (1) the machined surface of the saddle groove is qualified as Grade I; (2) Other machined surfaces are qualified as Grade II. The sample of steel casting shall be subject to radiographic inspection, and shall be evaluated as per GB/T5677-1985, and it is qualified as Grade II. For steel castings whose actual thickness is greater than the maximum thickness that can be detected by radiographic testing, ultrasonic testing is allowed to replace radiographic testing. It is evaluated in GB/T7233.1-2009 and is qualified as Grade I.
2) The product quality shall meet the relevant provisions of the contract, drawings and signed Steel Casting Technology and Quality Agreement.
3) Four test bars shall be cast on each product with enough gas cutting allowance to ensure that the size of the test bar is not less than 350 mm long × Width 50 mm × The thickness is 50 mm, which shall not be completely cut off from the product at the time of delivery, and the physical and chemical testing data shall be used as one of the basis for determining whether the product is qualified. The font and size of the cast type shall be consistent, and the direction shall be upward, and its position shall avoid the lifting lug welding position.
4) The products can only be delivered after passing the inspection (self inspection), and relevant inspection reports shall be issued. The original of the relevant inspection report or technical data of the product shall accompany the goods. A complete set of data including all test reports shall be provided for each product, which shall be in both Chinese and English. If the data is incomplete, the user has the right to refuse the acceptance.
It can be seen from the quality and technical requirements that the quality of this steel casting is very strict. In order to produce this steel casting well, it must be guaranteed that there are no casting defects.