GB 9948-1988 Seamless Steel Tubes for Petroleum Cracking

GB 9948-1988, “Seamless Steel Pipes for Petroleum Cracking”, is a Chinese standard that specifies the classification and technical requirements for seamless steel pipes used in the petroleum cracking industry.

Seamless steel pipes for petroleum cracking are mainly used for conveying crude oil, natural gas, and other petrochemical products in the oil and gas industry. They are divided into two categories: factory-made pipes and field-made (or field-welded) pipes. The steel pipes have a nominal external diameter of 10mm to 101.6mm and an nominal wall thickness of 0.7 to 6.0mm.

The material requirements of GB 9948-1988 specify the chemical composition and mechanical performance requirements of steel pipes for petroleum cracking. Steel pipes shall be manufactured from raw materials of grade A and B on the basis of specified chemical composition and melting process. All steel pipes must be inspected by the manufacturers internal quality control system before leaving the factory and must meet the quality requirements specified in this standard.

The order of product delivery shall include the following information:

- Name and quantity of steel pipe;

- Name of manufacturer;

- Nominal diameter and wall thickness of steel pipe;

- Method of inspection used;

- Special requirements if necessary;

- Standard to which the steel pipes shall conform.

When the steel pipes are delivered, the manufacturer shall also provide a certificate of quality. The certificate shall include the following information:

- Name of manufacturer;

- Name and trademark of grade A and B steel used;

- Chemical composition;

- Mechanical performance test results;

- Chemical analysis certificate of raw materials;

- Heat treatment test results;

- Non-destructive inspection test results;

- Flattening and flaring test results;

- Finished product inspection certificate;

- Finished product packaging list;

- Other related test results and analyses if necessary.

Seamless steel pipes for petroleum cracking manufactured according to GB 9948-1988 must meet all the requirements specified in this standard. This standard applies to the design, manufacture, inspection and acceptance of seamless steel pipes for petroleum cracking. It is also applicable to other similar steel pipes. The requirements of this standard should be strictly followed, and any failure to comply may lead to product failure and dangerous consequences.

This standard GB 9948-1988 specifies the classification, technical requirements and test methods of seamless steel tubes for petroleum cracking. It applies to seamless steel tubes for oil refining in austenitic, ferritic, martensitic and duplex steels. This standard categorizes seamless steel tubes for petroleum cracking into three materials and seven classes.

The materials of seamless steel tubes for petroleum cracking specified in this standard are as follows: Material No. 0Cr13, No. 1Cr17, No. 00Cr17Ni12Mo2.

The categories of seamless steel tubes for petroleum cracking specified in this standard are as follows: Class I-X10CrMoVNb9-1; Class II-12Cr2MoG; Class III-1Cr18Ni9Ti; Class IV-X20CrNiMoTi; Class V.14Ni6Mo Cu; Class VI-47CrMo4; Class 7-U6 (0Cr13).

The technical requirements of seamless steel tubes for petroleum cracking are as follows: appearance and size inspection, mechanical properties, microstructure, chemical composition, non-destructive inspection by ultrasonic, hydrostatic and other tests.

The test methods of seamless steel tubes for petroleum cracking are as follows:

1. Appearance and size inspection: it mainly includes internal and external surface inspection, length measurement and geometric tolerances.

2) Mechanical Properties: It includes tensile strength, yield strength, elongation, flattening test, flaring test, ring breaking test, hydraulic expansion test and non-destructive test.

3. Microstructure: This test mainly includes metallographic structure detection, ferrite content determination and grain size determination.

4. Chemical Composition: It includes chemical composition analysis and carbon equivalent determination.

5, Non-destructive testing: It includes ultrasonic testing, hydrostatic testing and other tests.

This standard specifies the classification, technical requirements and test methods of seamless steel tubes for petroleum cracking. According to this standard, the usage performance of seamless steel tubes for petroleum cracking is improved and the quality is guaranteed. It is the basis of quality assurance for production, purchase and use of seamless steel tubes for petroleum cracking.