Malleable iron pipe fittings quality control process
First, the main factors affecting the treatment effect
Mary pipe pieces dealing with the right amount because of its range of metamorphism element requires very narrow, and thus more difficult to stabilize than ductile iron. This requires that the relevant process factors must strive to do less volatility. Treatment effect of malleable iron pipe fittings larger process factors are mainly the following aspects.
1, the sulfur content of the original hot metal
Elemental sulfur consumption deterioration. It has a very strong force of hot metal sulfur and high magnesium, cerium, calcium, there are more modifier is vulcanized into the slag, thereby reducing the ability to cause deterioration of unsuccessful treatment. Therefore, in the production of malleable iron pipe fittings should try to use low sulfur-containing pig iron and coke. Conditions, take advance measures for desulphurization is beneficial. This is not to say that with a higher sulfur content of the molten iron can not be successfully processed malleable iron pipe fittings. Many domestic and foreign factories with a sulfur content of up to 0.06-0.08% of hot metal cupola can be stably produced malleable iron pipe fittings, but deterioration of the alloy to be used in an amount more. Information on experiences with 0.07-0.13% sulfur hot metal production of compacted graphite cast iron that under certain conditions, such as titanium to expand the scope of action from the use of anti-ball effect of sulfur. Nevertheless, the amount of sulfur is stable processing malleable iron pipe fittings necessary requirements.
2, the processing temperature of molten iron
When the molten iron low temperature treatment Gao had a significant impact on the absorption rate of the alloy, especially magnesium-based vermicularizing even more so. The higher the temperature, the more violent boiling magnesium gasification, burning the more less, some as low as possible so that the processing temperature as well. Document describes when using magnesium titanium composite modifier processing malleable iron pipe fittings, the effects of different treatment temperature on treatment efficiency. Processing at 1400 ℃, the worm-like graphite in more than 95%, the ball rarely; at 1280 ℃ treatment, more than half of the graphite nodules. Alloy amount is the same, the processing temperature of the large visible absorption rate.
In actual production, the temperature must be considered to determine the process for casting pouring temperature requirements. However, the processing temperature must be as stable as possible, if the temperature fluctuation is large, the amount must be adjusted alloy, otherwise it is difficult to ensure the quality of treatment.
Rare earth-based vermicularizing, the processing temperature is higher Advantageously, the temperature is too low is not easy even, not even fully melted alloy, thus affecting the treatment effect.
3. Processing operations
Since the creep process of the process due to fluctuations in response tangled sensitive, thus requiring operation advised to strictly accurate. Uniformity of the alloy composition, alloy covering the case, quantitative and iron alloys, slag slag and other measures, such as have a direct impact on the treatment effect.
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