1. Flux drying and heat preservation control

Flux before use as stipulated in the flux manual baking in the first place, the drying process specification is according to the test and inspection control, quality assured get accurate data, this is a kind of enterprise standards, requirements of different enterprises have different specifications, secondly according to JB4709-2000 < < steel pressure vessel welding procedures > > recommended flux drying temperature and holding time.General flux drying, stacking height is not more than 5cm., welding materials often in a drying number of generations, in the stacking thickness of thick thin, this should be strictly managed to ensure the drying quality of flux.Avoid piling thickness is too thick, by extending the drying time to ensure flux drying.

2 field management of flux and control of recovery and disposal

Welding site should be cleaned, do not mix the debris into the flux, including flux pad flux should be issued according to regulations, preferably at about 50℃ to be used, timely do a good job of flux recycling, to avoid pollution;Continuous use of flux with 8 mesh and 40 mesh sieve respectively and remove impurities and fine powder, mixed with three times the new flux after use.Before use, it must be dried at 250-350℃ and kept for 2 hours. After drying, it should be stored in an incubator at 100-150℃ for next use. It is forbidden to store in the open air.In case of complex site or relatively high humidity, timely manage the operation site, keep it clean, conduct necessary tests of flux resistance to moisture and mechanical mixture, control moisture absorption rate and mechanical inclusions, avoid disorderly heap and confusion of flux.

Size and distribution of flux particles

Flux has a certain granularity requirements, the particle size should be appropriate, so that the flux has a certain air permeability, welding process is not permeable continuous arc light, avoid air pollution weld pool forming pores.There are two types of flux, one with a normal size of 2.5-0.45mm(8-40 mesh) and the other with a fine size of 1.43-0.28 mm(10-60 mesh).Fine powder less than the specified size is generally not more than 5%, larger than the specified size of coarse powder is generally more than 2%, to do a good job on the flux particle size distribution test and control, determine the use of welding current.Attachment: relationship between flux size and welding current range

Particle size /mm 2.5-0.45 0.28-1.43 welding current /A < 800 600-1200

Control of flux size and bulk height

If the flux layer is too thin or too thick, it will cause pits, spots and pores on the weld surface, forming an uneven bead shape. The thickness of the flux layer should be strictly controlled in the range of 25-40mm.When using sintered flux, the flux stack height is 20%-50% higher than that of fused flux due to the low density.The larger the wire diameter is, the higher the welding current will be.As the welding process is not standard operation, the disposal of fine powder flux is not reasonable, the weld surface will appear intermittent uneven pits, non-destructive testing qualified but the appearance quality is affected, partially weakened shell thickness.