This is a technical standard specifically for titanium alloy bolts used in high-performance fields such as aerospace.It not only specifies the size of the bolts, but also a comprehensive specification of materials, performance, craftsmanship, and inspection.
1. Scope of application and materials
Material: The standard clearly stipulates that the bolts are made of titanium alloy, and the commonly used grades include：
TC4: The commonly used titanium alloy, namely Ti-6Al-4V, has good overall properties (strength, toughness, corrosion resistance).
TA2: Industrial pure titanium, relatively low strength, but better plasticity, corrosion resistance, and formability.
Others such as TB3, TC16, etc. may also be selected according to performance requirements, depending on the performance level of the bolt.
Performance level: The standard defines the strength/performance level of the bolt, such as：
1100 MPa grade
900 MPa grade
Shear-resistant type, etc.
Different grades correspond to different materials, heat treatment processes and mechanical properties indicators.
2. Technical content
The standard specifies the following key aspects：
Structure and size：
Reference is made to the bolt structure forms (such as hexagonal head, countersunk head, twelve corners, etc.) in the national standard and navigational signs.
The size series must meet relevant standards (such as thread specifications, head size, rod length, etc.).
Technical requirements：
Mechanical properties: Specify the values satisfied by tensile strength, yield strength, elongation, cross-section shrinkage, shear strength, etc.
Thread: High accuracy requirements, usually 6g or higher, need to pass the thread through and stop gauge inspection.
Surface treatment：
Anodizing treatment: More common, an oxide film is formed on the surface, which is used for anti-corrosion, identification (different colors represent different grades) and wear resistance.
Silver-plated or copper-plated: used in situations where conductivity or special lubrication and anti-bite are required.
Coated dry film lubricant: used to control the tightening torque and prevent bite.
Surface defects: There are strict restrictions on cracks, folds, dents, etc.
Hydrogen content control: Titanium alloys are easy to absorb hydrogen and cause hydrogen embrittlement. The standard has a strict upper limit on hydrogen content.
Inspection and test methods：
100% inspection: usually includes appearance, size, and thread.
Sampling inspection (batch nature): including mechanical properties testing (tensile, shear), hydrogen content analysis, metallographic organization inspection, surface corrosion inspection, etc.
Torque test: Assess the assembly performance of bolts.
Marking, packaging and storage：
Signs are usually required on bolts, including material grade, performance grade, manufacturer code, etc.
The packaging needs to be moisture-proof, anti-collision, individually packed or use anti-rust paper/bag.
The storage environment requires dryness and ventilation.
3. How to obtain or order ”QJ2580 specification" bolts?
You can't just say “QJ2580 bolt” like buying ordinary bolts, because this standard is a “general specification”, not a specific part drawing number.You need to provide more detailed information：
Complete standard number + specific part standard：
For example: QJ 2580-2003 as a general requirement, cooperate with QJ 3146.1 (a certain hexagonal head bolt standard), and specify specifications, such as M6x30.
The complete expression may be: titanium alloy bolt QJ 3146.1 M6x30, performance grade 1100Mpa, material TC4, accepted according to QJ 2580-2003.
Drawing requirements：
In actual aerospace projects, a bolt is usually a part on engineering drawing paper.The drawings will refer to QJ2580 as the general specification, and at the same time specify all the details such as specific size standards, performance levels, and surface treatment.
QJ2580 is the “quality assurance Certificate” and “technical outline” of high-end titanium alloy bolts.
It represents high reliability, high strength, lightweight and corrosion resistance.
Behind it is a set of strict quality control system.
When ordering, it must be combined with specific structural size standards, performance levels and drawing requirements.
