This requires that the flux must have good metallurgical and technological properties; The particle size meets the requirements (the particle size of ordinary flux is 0.45~2.50mm, the fine particles below 0.45mm shall not be more than 5%, and the coarse particles above 2.50mm shall not be more than 2%; the particle size of fine flux is 0.28~1.425mm, the fine particles below 0.28mm shall not be more than 5%, and the coarse particles above 1.425mm shall not be more than 2%); Water content w (H2O) 0.10%; The content of mechanical inclusions shall not be greater than 0.30% (mass fraction); Sulfur and phosphorus content w (S) 0.060%, w (P) 0.080%.
According to the selected welding wire material and the chemical composition of the valve body material, the high silicon melting flux or high basicity sintering flux is mostly selected.

Broaden domestic sales channels and build independent brands
At the moment when external demand continues to be weak, the transfer of export to domestic sales is regarded as a good medicine to digest excess capacity. As for most export trading companies that are accustomed to producing on orders, the transfer of export to domestic sales has become more and more important.
The form of foreign sales is completely different from that of domestic sales. Foreign trade is to follow up after receiving the order, and then produce and deliver; Domestic sales demand forms different management teams to build new sales channels. The transformation of foreign trade companies will not be indomitable, and the demand will break through its own bottlenecks and cross many thresholds.
Professional experts of stainless steel hose believe that it is a general trend to pay equal attention to domestic and foreign trade in the future, while in the process of export to domestic sales, brand building is a long-term project, and path building is the top priority. They analyzed that under the impact of the financial crisis, overseas orders from Europe and the United States were significantly reduced, and the company's economic benefits were gradually declining. In order to seek new living conditions, many companies that opened up foreign shopping malls moved to domestic shopping malls.