Straight thread connection sleeve quality is an important part of ensuring the quality of the joint, the production quality can be controlled from the following three aspects: sleeve size control: the design of the sleeve size, should make a net cross-sectional area of ??the sleeve and the sleeve material strength of the product is greater than the standard steel reinforcement area and 1.1 times the strength of the product; internally threaded sleeve should meet the functional requirements of the product, its tolerance zone should use raw material control 6H or 7H sleeve: sleeve should choose high strength, good ductility. easy processing and low prices of steel to manufacture, usually 45 high-quality carbon structural steel, can also be used high strength low alloy structural steel. Have qualified raw material suppliers to ensure that qualified raw performance and stability. Pre-production and processing of raw materials to the mechanical properties of a sample re-examination. Quality control of the production process sleeve: sleeve production from the rough to finished each process should have a strict sampling system and quality control standards, the surface should be finished production batch tag.