Submerged Arc Welding Flux Manufacturer: Application Characteristics of Submerged Arc Welding Flux

Submerged Arc Welding Flux Manufacturer: Application Characteristics of Submerged Arc Welding Flux 
Submerged Arc Welding Flux Manufacturers: Submerged arc welding fluxes are generally classified into two main types: fused fluxes (such as HJ350 and HJ431) and sintered fluxes (such as SJ101 and SJ201). Currently, some welding units employ submerged arc welding equipment, which has led to differences in the application of sintered fluxes compared with fused fluxes. In recent years, sintered fluxes have accounted for 80% of the market share, while the use of fused fluxes has steadily declined. In fact, each type has its own advantages and disadvantages; when used appropriately, they can help avoid many unnecessary complications. 
Submerged Arc Welding Flux Manufacturer: I. Application Examples 
1. Application of SJ101 on Carbon Steel Rollers 
The 64-mm-thick SA515 Gr60 boiler shell was welded using submerged arc welding with EM12 welding wire and SJ101 flux. Post-weld PT inspection revealed transverse cracks throughout the weld, prompting removal of a 10-mm-wide bead by carbon arc gouging. Subsequent PT inspection still showed transverse cracks, although the base metal, welding wire, and flux all met specifications. It was then decided to completely remove the original weld and replace the SJ101 flux with HJ431; following PT and RT inspections, all welds were found to be fully compliant. 
2. Application of SJ101 in the 19Mn6 Steam Drum 
On the 19Mn6 drum, all manufacturers use SJ 101 flux. Currently, this sintered flux is undergoing testing and is being compared with fluxes from Jinzhou Wande, Atlantic, Little Swan, and Luoyang Peony. The results show that Wande and Atlantic, as well as Jinzhou, exhibit varying degrees of welding defects and poor slag removal performance. In contrast, Little Swan, Peony, and Luoyang Peony demonstrate superior overall performance. Compared with the test results for H08MnMoA HJ350, impact toughness is slightly improved, while other properties remain essentially unchanged. 
Submerged Arc Welding Flux Manufacturer: II. Comparison Between Flux Sintering and Flux Smelting 
A: Sintered flux 
Manufacture and characteristics of sintered flux: One type of flux is prepared by blending various powdered ingredients in specific proportions with an appropriate binder, followed by mixing, stirring, and granulation. The resulting granules are then sintered at 750–1000°C to form compact blocks, which are subsequently crushed and screened. A notable characteristic of sintered flux is its tendency to absorb moisture, which can adversely affect its performance; therefore, specific handling and storage requirements must be observed both during use and storage. 
B: Smelting Flux 
Manufacturing characteristics of smelting flux: In the production of smelting flux, various raw materials are mixed in specific proportions and then melted in an electric furnace at a high temperature of 1400–1700°C. The molten mixture can be granulated in water or poured onto a cooled steel plate. It is then dried, crushed, and screened to finally produce the finished flux. 
Characteristics of flux melting: excellent chemical homogeneity; the powder can be removed without affecting the flux composition; the flux does not absorb moisture, thereby simplifying storage; when particle size and composition remain stable, it can be reused via a wire-feeding recycling system. However, certain regulations prohibit the reuse of flux. 
Smelting flux and sintered flux: Smelting flux HL 431 is priced at RMB 4.35 per kilogram, while sintered flux SL 101 costs RMB 5 per kilogram; thus, the smelting flux is relatively cheaper. Closing remarks 
Submerged-arc welding flux manufacturers: As illustrated by the foregoing cases, sintered flux exhibits excellent slag-removal performance; however, it is highly hygroscopic, and manufacturing processes vary among different producers, making process control relatively challenging. Therefore, when using such flux, it is advisable to conduct comparative weld tests with fluxes from multiple manufacturers, as the same material may yield differing welding results. In fact, both sintered flux and fused flux have their respective advantages and disadvantages. To ensure production schedules and profitability, companies generally do not need to switch between carbon steel and low-alloy steel fluxes as long as the current flux performs well. Moreover, the composition of sintered flux can fluctuate significantly, and different manufacturers employ varying application methods; while a particular formulation may prove successful in laboratory testing, problems are more likely to arise during large-scale production. Consequently, flux and welding wire should be matched and used together whenever possible, and substitutions should be avoided unless absolutely necessary, in order to maintain smooth production operations. If it becomes necessary to change to a different type of welding wire or flux, a new assessment of the manufacturing process must be carried out.