Use solder law maintenance tractor is cast-iron when, except the basis actual condition choice solders aptly outside the method, still should notice the following item: One, place should solder weldment to reach all harmful impurity all round its to be like ferruginous, smeary, paint to wait to keep clear of clean thoroughly before the preparation before solder solders; When solder filling crackle if weldment wall is large,be less than 25 millimeter, should get what 4 millimeter control a diameter to stop crack aperture; Some weldment even according to the wall thick the type of requirement choice groove with craft. 2, of welding rod and its diameter those who choose different type is cast-iron a welding rod that should choose its correspondence; Its diameter basically fills according to weldment solder the ply of place will decide; To prevent white mouth and the generation that soldier fire organizes, reduce heat to affect an area, use small diameter welding rod more at present. 3, the choice of power source polarity is when dc arc welding, pass greatly to avoid frit big, weldment overheat and burn wear, use reversal sex to join, namely weldment, receive cathode, welding rod receives positive pole. 4, the Guo Darong of choice electric current of voltaic intensity is deep increase, weldment metal component and impurity diffuse to bath changed welding line property; Electric current crosses small conference to affect the stability of electric arc, easy generation slag inclusion, the blemish such as air hole; The choice of voltaic intensity should be in according to crackle or blemish the space of weldment conduct, return brand of welding rod of Lv of take an examination and diameter at the same time. 5, solder operation point should avoid solder filling area as far as possible to reduce crackle local overheat, grow break to answer discontinuous, section jumps solder; To reduce frit deep, should choose small electric current, fine welding rod, apply solder with short Gu as far as possible; Better to plasticity welding rod is like nickel radical welding rod, cupreous iron welding rod, round head little weight should be used instantly after solder light knock welding line, with flabby welding stress, cleared crackle and stoma; Wave of every small solder does not want at the same time over or across arrives slope day two side, such is helpful for not solder part freedom is contractive, and avoid electric arc stay in groove both sides too long; Solder layer should be enclothed to ground floor make rock-bottom anneal, change go its machine function. CNC MillingCNC Machining