Knowledge

06Jan, 2026

50. What is the main component of the dry process solvent?
The commonly used "dry method" solvents mainly consist of the following components: (1) Hydrochloric acid (HCl) with a concentration of 31% (360 g/L, Boehme degree above
05Jan, 2026

49. What is the main component of the wet-process flux?
The commonly used "wet-process" fluxes primarily consist of two types: one employs ammonium chloride (NH₄Cl) as the sole flux, while the other uses a mixture of ammonium
04Jan, 2026

48. What is the solvent method? What is the purpose of using solvents?
After acid washing and cleaning, or following immersion in dilute hydrochloric acid solution prior to hot-dip galvanizing, steel pipes must first be coated with a layer of concentr
31Dec, 2025

47. What is the purpose of cleaning?
After acid washing, steel pipes must be immediately immersed in flowing cold or hot water to remove residual acids, iron salts, and carbon particles that hinder hot-dip galvanizing
30Dec, 2025

46. What aspects are covered in the self-inspection process for pickling?
Self-inspection by pickling workers is a critical step in quality control for their steel pipes. Only through collective quality management can we ensure minimal or no defective pr
29Dec, 2025

45. Why must steel pipes be cleaned immediately after acid washing?
After being removed from the pickling solution, steel pipes must be immediately rinsed with water to prevent the following issues: (1) It stops the pickling solution from continuin
26Dec, 2025

44. Why do you need to lift and lower the steel pipes several times during th...
In the acid pickling process of bundled steel pipes, it is common to observe that the pipes being pickled in the tank are periodically lifted and lowered several times. This is the
25Dec, 2025

43. Why is it effective to swing the steel pipe or circulate the solution dur...
When performing acid pickling on steel pipes, three key observations emerge: First, oscillating the pipes or using steam to agitate the pickling solution significantly enhances the
24Dec, 2025

42. Why is the multi-channel method superior to the single-channel method in ...
The steel pipe undergoes sequential pretreatment in an acid bath with low concentration but high iron salt content. During this stage, the acid solution temperature can be elevated
24Dec, 2025

41. Why is steam direct heating commonly used for pickling solutions? What ar...
Direct steam heating in pickling solutions is widely adopted due to its operational simplicity, high heating efficiency, and stirring effect that accelerates pickling rates while e
24Dec, 2025

40. What are the heating methods for pickling solutions, and what are their r...
Common heating methods for pickling solutions include direct steam pipe heating, steam nozzle heating, steam heating pipe heating, electric heating elements, flame immersion heatin
24Dec, 2025

39. Why does a distinct cluster of corrosion pits appear on the surface of we...
Welded steel pipes are prone to developing corrosion pits along longitudinal weld seams after acid pickling, particularly in gas-welded and furnace-welded pipes. This phenomenon pr

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