Low alloy high-strength steel is a common building material used in construction sites, and is a type of structural steel used in low-carbon engineering. It has a very low carbon content, which is slightly lower than ordinary steel. However, this material can be formed through hot processing and has good weldability. It is also a very cold and brittle material, which is relatively resistant to high temperatures Low alloy high-strength steel can be divided into three categories based on its main properties and uses: high-strength steel, low-temperature steel, and corrosion-resistant steel. Today, we will focus on introducing the testing items and standards for general structural and engineering low alloy high-strength structural steel plates, profiles, and steels
1. Steel grade and chemical composition
The grade and chemical composition (melting analysis) of hot-rolled steel should comply with the provisions of Table 1 in GB/T1591, and its carbon equivalent value should comply with the provisions of Table 2.
The grades and chemical composition (melting analysis) of normalized and normalized rolled steel should comply with the provisions of Table 3 in GB/T1591, and its carbon equivalent value should comply with the provisions of Table 4 The grade and chemical composition (melting analysis) of thermomechanically rolled steel should comply with the provisions of Table 5 in GB/T1591, and its carbon equivalent value should comply with the provisions of Table 6 in GB/T1591. When the carbon content of thermomechanically rolled steel is not greater than 0.12%, the welding crack sensitivity index should be used instead of carbon equivalent to evaluate the weldability of the steel. The sensitivity index should comply with the provisions of Table 6 in GB/T1591 The carbon equivalent is calculated from the melting analysis composition according to the prescribed formula In order to improve the performance of steel, it is agreed between the supply and demand parties that alloy elements other than those specified in Tables 1, 3, and 5 can be added to the steel. The machine content of the alloy elements should be indicated in the quality certificate When the purchaser requests to ensure thickness oriented performance of steel plates, the sulfur content should comply with the provisions of GB/T53132. Smelting method
The steel is smelted by a converter or electric furnace, and if necessary, it can be refined outside the furnace.
. Unless the purchaser has special requirements and is specified in the contract, the smelting method is generally chosen by the supplier3. Delivery status
The steel is delivered in the hot rolled, normalized, normalized rolled, or thermally mechanically rolled (TMCP) state 4. Mechanical and Technological Properties
Tensile: The tensile properties of hot-rolled steel should comply with the provisions of Table 7 and Table 8 in GB/T1591 The tensile properties of normalized and normalized rolled steel should comply with the provisions of Table 9 in GB/T1591 The tensile properties of YMCP steel should comply with the provisions of Table 10 in GB/T1591 According to the requirements of the purchaser, the reduction of area in the thickness direction of the steel should comply with the provisions of GB/T5313 For steel plates and strips with a nominal width of no less than 60mm, transverse tests are taken for tensile testing, while longitudinal specimens are taken for tensile testing of other steels
Function of testing report:
1. Project bidding: Issue authoritative third-party CMA/CNAS qualification report
2. Online e-commerce platform entry: Quality inspection report recognized by major e-commerce platforms 3. Used as a sales report: issuing legally effective testing reports to make consumers more confident 4. Papers and research: Provide professional personalized testing needs 5. Judicial services: providing scientific, fair, and accurate testing data 6. Industrial problem diagnosis: Verify the troubleshooting and correction of industrial production problemsBaijian and testing process:
1. Telephone communication and confirmation of requirements
2. Recommend solutions and confirm quotations 3. Mail samples and arrange testing 4. Progress tracking and result feedback 5. Provide reports and after-sales service 6. If urgent or priority processing is requiredTesting and testing characteristics:
1. The testing industry is fully covered, meeting different testing needs
2. Fully cover the laboratory and allocate localized testing nearby3. Engineers provide one-on-one services to make testing more accurate
4. Free initial testing, with no testing fees charged
5. Self service order delivery for free on-site sampling
6. Short cycle, low cost, and attentive service 7. Possess authoritative qualifications such as CMA, CNAS, CAL, etc 8. The testing report is authoritative and effective, and is generally used in China