Introduction
Zirconium and zirconium alloys are commonly used in industrial applications, due to their excellent corrosion resistance and high temperature creep resistance. The most common type of zirconium and zirconium alloy rods and wires are Grade 90/2, Grade 120/2 and Grade 180/2 rods and wires.
This paper will provide an overview of GB 8769-88, a Chinese standard for the inspection and acceptance of zirconium and zirconium alloy rods and wires for industrial use. It will discuss the requirements for the chemical composition, mechanical properties, microstructure, and surface quality of the rods and wires, as well as the inspection methods used to verify the quality of the rods and wires.
Chemical Composition Requirements
One of the key requirements of GB 8769-88 is to ensure that the rods and wires comply with the chemical composition requirements for zirconium and zirconium alloy rods and wires for industrial use. The required chemical composition for rods and wires of Grade 90/2, Grade 120/2 and Grade 180/2 is listed in Table 1.
Table 1: Chemical Composition Requirements for Grade 90/2, Grade 120/2 and Grade 180/2 Zirconium and Zirconium Alloy Rods and Wires
Element Grade 90/2 Grade 120/2 Grade 180/2
Zirconium 89.7-91.5 118.7-121.5 178.7-181.5
Iron 0.5-2.5 0.5-2.5 0.5-2.5
Oxygen 0.20-0.60 0.20-0.60 0.20-0.60
Nitrogen 0.03-0.05 0.03-0.05 0.03-0.05
Titanium - 0.030-0.150 0.030-0.150
The chemical composition of the rods and wires is determined using a combination of standard chemical analysis methods, such as atomic absorption spectroscopy (AAS), X-ray fluorescence spectrometry (XRF), and Inductively Coupled Plasma (ICP) spectrometry.
Mechanical Property Requirements
Another key requirement of GB 8769-88 is to ensure that the rods and wires comply with the mechanical property requirements for Grade 90/2, Grade 120/2 and Grade 180/2 zirconium and zirconium alloy rods and wires. These requirements specify that the tensile strength, yield strength, and percentage elongation must meet a certain requirement. The required mechanical properties are listed in Table 2.
Table 2: Mechanical Property Requirements for Grade 90/2, Grade 120/2 and Grade 180/2 Zirconium and Zirconium Alloy Rods and Wires
Grade Tensile Strength (MPa) Yield Strength (MPa) % Elongation
90/2 ≥400 ≥250 ≥10
120/2 ≥650 ≥400 ≥8
180/2 ≥800 ≥550 ≥7
The mechanical properties of the rods and wires are determined using standard testing methods, such as tensile testing and bend testing.
Microstructure Requirements
Another important requirement is to ensure that the microstructure of the rods and wires conforms to the requirements of GB 8769-88. The microstructure requirements specify that the rods and wires must have a homogeneous and stable microstructure, with no intermetallic compounds or other non-metallic inclusions. The microstructure requirements are verified by microscopic examination.
Surface Quality Requirements
Additionally, GB 8769-88 specifies requirements for the surface quality of the rods and wires. The requirements specify that the rods and wires must be free of surface defects, such as pits, cracks, or seams. The surface quality requirements are verified by visual inspection.
Inspection and Acceptance
To ensure that the zirconium and zirconium alloy rods and wires meet the requirements of GB 8769-88, the rods and wires must undergo inspection and acceptance testing. The inspection and acceptance process consists of chemical composition inspection, mechanical property testing, microscopic examination, and visual inspection. If the rods and wires are found to be non-conforming, the supplier must take remedial measures and re-test until the rods and wires are found to be conforming.
Conclusion
GB 8769-88 is a Chinese standard for the inspection and acceptance of zirconium and zirconium alloy rods and wires for industrial use. This standard specifies the requirements for the chemical composition, mechanical properties, microstructure, and surface quality of the rods and wires, as well as the inspection methods used to verify the quality of the rods and wires.
