Casting condition the fusion of nodular cast iron

The Mg) of 6% . Press GB regulation, the content tolerance of each brand Mg and RE is ± 1% , differ up and down 2% , rudimental Mg and carbon (quality mark) can differ 0.

01% ～ 0.

015% , contain the error of temperature of fluid of sulfur content, iron and taphole quantity plus iron fluid, the discrepancy of Mg, C will be bigger. Accordingly, my factory changes agent of agent, be pregnant with to the ball (if the deviation of main element content such as Mg, RE, Ba) is controlled,be in ± 0.

3% less than, close-grained to fracture surface degree, granuality also raises technical requirement, meet those who reduce a ball change agent of agent, be pregnant with to close so that lead otherwise, influence ball is changed, the stability of be pregnant with. One, the choice of chemical composition (1) C carbon promotes graphitization, reduce white mouth, reduce cementite and 3 yuan of phosphor namely in all brilliant, increase ferrite. Carbon can promote magnesian absorptivity, raise a ball to turn the result, still can improve liquidity, increase caky the bulk when expands. Accordingly, my factory adopts taller carbon equivalent to be premise, the carbon raw iron fluid (quality mark) control is in 3.

6% ～ 3.

8% , carbolic equivalent (CE) control is in 4.

6% ～ 4.

8% . (2) Si silicon promotes graphitization apparently, make in all brilliant temperature is elevatory, in all brilliant contains carbolic quantity to reduce, should will eventually silicon is measured (quality mark) control is in 2.

8% ～ 2.

9% . (3) Mn manganese is in easily arise on brilliant round border in all slant fold, reduce tenacity, intensity thereby, because of this manganese (quality mark) ordinary control is in 0.

3% the following. (4) P phosphor does not have apparently bad influence to the mechanical function of nodular cast iron, but when rubidium ﹥ 0.

05% when, slant easily round border of analyse Yu Gongjing, form n duality or 3 yuan of phosphor in all brilliant, serious exasperate and mechanical function, reason should reduce the amount that contain phosphor. According to the manufacturing condition of my factory, control cries, ﹤ 0.

05% . (5) S sulfur and affinity of magnesian, rare earth are very strong, the ball in can draining iron fluid changes elemental Mg and RE, form MgS and RES broken bits. Additional, sulfur content still can cause increase of sulfide slag inclusion too much, make mechanical function drops, and easy form the blemish such as slag inclusion, hypodermic stoma, because this answers control is sweet Ws ﹤ 0.

03% , and how many according to sulfur content, increase or reduce a ball to change agent dosage. 2, fusion equipment and material 1. The choice iron fluid of fusion equipment gives furnace temperature to spend the foundation that is manufacturing nodular cast iron, below the premise that my factory needs in contented production technology, follow the principle of efficient, low cost, use 5t ／ H fusion of cupola of sirocco of two big span, taphole temperature is 1480 ～ 1520 ℃ , satisfied the requirement that produces nodular cast iron basically. 2. The control of raw material (1) fusion nodular cast iron chooses a vendor surely with cast iron choice, bases accords with GBl412-1985. Melt down iron and miscellaneous steel should pile up alone, make sure raw material is pure, this is nodular cast iron of manufacturing high quality one of crucial link. (2) ball changes agent of agent, be pregnant with to be made up alone, composition sees next tables. My factory handles iron fluid with bag of Lt iron fluid, the ball changes agent granuality to be 5~25mm, granuality of agent of be pregnant with is 3~5mm. Ba, Ca, RE and oxygen, nitrogen, sulfur has very strong adhesion, the intention that the ball changes is promoted since one part among them, easy rise of formation oxide, nitride and sulfide is eliminated to iron fluid surface; Another part regards black lead as the particle of core. And Bi is a kind of very strong exterior active element, restrict thereby in all the growth of brilliant group and black lead, raise a ball to change with be pregnant with fight decline ability, also increased the form nucleus capacity of black lead. (3) chooses high grade coke to should control the sulfur content <0 of coke. 06 ％ , ash content ≤ 12% . 3, the method that my factory handles to nodular cast iron uses processing technology ladle of type of 1 T dikes and dams, in the ball the circumstance that iron of residual, incomplete does not have inside indentation of the bottom that spend a bundle falls, join 1. 8 ％ are controlled (contain sulfur content to increase according to iron fluid or decrease) the ball changes an agent, enclothe above 0. The agent of FYF-1 be pregnant with that 9 ％ control is pounded solid, build an ancient stemmed cup or bowl of clean iron of nodular cast iron in surface of agent of be pregnant with next. First time is irruptive 3 iron of 2 ／ fluid (erupt time 2~3min) , await reaction smooth fullback is entered the rest of L ／ 3 iron fluid, even inside taphole chamfer ground adds agent of be pregnant with, scatter on agent of collect broken bits, gather up the broken bits of surface of clean iron fluid child, pouring trigonometry test block undertakes the ball turns judgement. Enclothe agent of broken bits of a collect to undertake protecting preventing to answer sulfur blandly again in iron fluid surface next. After trigonometry test block judges case of ball chemical combination can pouring. Means of be pregnant with uses the breed end the bag, packets taphole chamfer be pregnant with is big turn when packet, with along with shed be pregnant with and chunk float silicon (75FeSi) be pregnant with. Make through be pregnant with the free cementite of nodular cast iron decreases considerably, the ball changes grade to rise greatly, the black lead ball of unit area counts grow in quantity. Aggrandizement be pregnant with is the core that produces nodular cast iron, to add ferrite content, to nodular cast iron should come to change in refrigeration box opens under temperature. 4, epilogue (it is place of manufacturing ferrite nodular cast iron is necessary that 1) chooses equal chemical class status. (2) ball is changed the person's right amount Ca is added in agent and agent of be pregnant with, and join in iron fluid bag a few the alloying element such as bismuth, the ball Chinese ink that can raise unit area significantly is counted. (Afore-mentioned 3) balls change a processing technique to suit production of batch of nodular cast iron. When using liquid of cupola fusion iron, use low Mg ball to change an agent to be able to make reaction calm, the ball changes quality stable and reliable. CNC Milling