Knowledge

1. Substandard Chemical Composition: Deviations in the alloy element ratio during billet smelting, with core elements such as carbon, manganese, and c

1. Chemical Composition Verification: Quantitative analysis of core elements such as C, Mn, and Cr is performed using equipment such as direct-reading

1. Preparation before re-inspection: Clearly identify the grade of the steel pipe to be re-inspected and its corresponding standard (e.g., GB/T 8162,

1. Appearance Quality Inspection: Qualified products should have a smooth and flat surface, free from defects such as cracks, folds, scars, pits, and

I. Chemical Treatments 1. Pickling and Passivation: Pickling removes surface oxide scale and weld spots, forming a dense passivation film. This is the

I. Precise Matching Based on Usage Scenarios Different operating conditions have significantly different core requirements, allowing for direct matchi

I. Chemical Treatments Acid Pickling and Passivation: Acid pickling removes surface oxide scale and oil, forming a dense passivation film. This is the

I. Prioritize Selection Based on Core Operating Conditions Ordinary Indoor Dry Environment: Phosphating + Rust-Inhibiting Oil Coating – Low cost

I. Chemical Treatments Acid Pickling and Passivation: Acid pickling removes surface oxide scale and oil stains, forming a dense passivation film. This

1. Consider the application scenario: If the pipes are used outdoors in humid, corrosive environments, underground, or in clean environments such as f

I. Chemical Treatments 1. Pickling and Passivation: Pickling removes surface oxide scale, oil, and weld spatter, forming a dense passivation film. Thi

I. Core Cost Factors Raw Material Costs: Fluctuations in the prices of upstream raw materials such as steel billets, ferrochrome, and iron ore directl