CN101259533A

CN101259533A - Production technology of iron base powder metallurgical fire cover

Info

Publication number: CN101259533A
Application number: CNA2008100237100A
Authority: CN
Inventors: 龙斌; 包敢锋
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-18
Filing date: 2008-04-18
Publication date: 2008-09-10
Anticipated expiration: 2028-04-18
Also published as: CN100553830C

Abstract

The invention relates to a production process of an iron-based powder metallurgy fire cover, which comprises the following steps: powder metallurgy raw material is formed by mixing atomized Fe powder of less than 100 meshes and a compound lubricant in the environment without carbon source, the weight percentage of the atomized Fe powder of less than 100 meshes and the compound lubricant is: 99.5 percent atomized Fe powder of less than 100 meshes and 0.5 percent compound lubricant; the compound lubricant is composed of lithium stearate, stearic acid and calcium oxalate, the weight percentages of the three are: 50 percent lithium stearate, 42 percent stearic acid and 8 percent calcium oxalate; the power metallurgy raw material which is prepared in step 1 is mixed in a clean double conic mixer with the speed of 19 to 21r/min for 60min, thus preparing powder metallurgy mixed material; the powder metallurgy mixed material which is prepared in step 2 is carried out the press forming to prepare a fire cover green compact; the green compact which is prepared in the step 3 is carried out the sintering at 1120 DEG C for 4h to obtain a powder metallurgy sintered compact; and the powder metallurgy sintered compact which is prepared in the step 4 is carried out the porcelain enamelling to obtain the iron-based powder metallurgy fire cover. The production process can successfully utilize the advantage of the powder metallurgy to produce the blocking fire cover, thus reducing the comprehensive cost by 40 percent.

Description

The production technology of iron base powder metallurgical fire cover

Technical field

The present invention relates to a kind of production technology of powder metallurgical fire cover.Belong to the powder metallurgy new material technology field.

Background technology

Along with economy constantly develops, living standards of the people improve constantly, to cause severe contamination, the thermal efficiency low be that the coal stove consumption of direct fuel reduces with coal, and increasing to the demand of gas-cooker, annual requirement is above 200,000,000.Blocking-up fire on the gas-cooker is built separated flame, is concentrated heating to improve the effect of the thermal efficiency, the temperature rise of reduction body of heater.Former aluminium casting+enamel or the punching press iron plate+enamel technology of always adopting.But because aluminium casting technology, can't be made the fire lid that needs complicated location because its temperature tolerance is lower than 700 ℃ and does not meet national standard, and use is not seen in the domestic market, and punching press iron plate technology only limits to planar products, and enamel adhesive force is low.A kind of cost of society need is suitable, can immediately blocking-up fire lid be dropped into the technology of producing in batches.

Summary of the invention

The objective of the invention is to overcome above-mentioned deficiency, the production technology of a kind of enamel strong adhesion, complex-shaped, iron base powder metallurgical fire cover that elevated temperature strength is high, with low cost is provided.

The object of the present invention is achieved like this: a kind of production technology of iron base powder metallurgical fire cover is to adopt＜100 orders atomizing Fe powder and compounded lubricant to be mixed into raw material in no carbon source environment, produces the burning-boosting cap blank by conventional powder metallurgical technique,

The two mass percent of described＜100 orders atomizings Fe powder and compounded lubricant is:

＜100 orders atomizing Fe powder 99.5%

Compounded lubricant 0.5%;

Described compounded lubricant forms by lithium stearate, stearic acid and calcium oxalate are composite, and three's mass percent is:

Lithium stearate 50%

Stearic acid 42%

Calcium oxalate 8%.

The powder metallurgical fire cover production technique is: batching → mixing → compacting → sintering → enamel → test package.Because enamel is 600 ℃ of high temperature coating processing, when the enamel product that finishes during to room temperature, must solve enamel layer and matrix expansion coefficient difference problem by the high temperature cold cut, not so the enamel layer of fragility and the toughness matrix coefficient of expansion differ, and enamel layer will break.Empirical tests, enamel material at the 0-950 ℃ of following coefficient of expansion is: identical with powder metallurgy ultra-low-carbon steel (C＜0.03%) coefficient of expansion, but the sintered steel coefficient of expansion and enamel between phosphorus content 0.03%-0.18% have than big-difference, so must adopt the carbon content in the special measure control powder metallurgical fire cover blank, cause＜0.03%C has relatively high expectations, and must adopt special measure to guarantee not introduce carbon source in process of production.But 620 ℃ of zinc stearate lubricant decomposition temperatures that powder metallurgy adopts at present are near 600 ℃ of C deposition reaction temperature: CO+ α Fe → CO ₂+ β Fe causes the product carburizing, and all decarburization finishes in sintering process thereafter, causes the enamel effect bad.Must use new lubricant for this reason, the complete decomposition temperature of this lubricant is necessary＜and 400 ℃, greasy property is not less than zinc stearate, discharges by pressed compact is inner for ease of lubricant low-temperature decomposition gas, increase the surface opening hole to improve enamel adhesive force, also need the part pore creating material.Through experiment, determined lubricant formulations to be: (lithium stearate 50%+ stearic acid 42%+ calcium oxalate 8%), wherein lithium stearate is reproducibility (decarburization) lubricant, and stearic acid is for reducing the decomposition temperature composition, and calcium oxalate is a pore creating material.Lithium stearate is determined in test according to decomposition temperature: stearic acid is about 5: 4 o'clock mixtures and decomposes (99.6%) temperature between 380-410 ℃, and it is 350 ℃ that calcium oxalate decomposes (99.5%) temperature, the requirement of the pore-creating before lubricant decomposes that meets the requirements.Measure calcium oxalate addition optimal value according to knockout press.Use this prescription lubricant to reduce by an order of magnitude with using zinc stearate lubricant product C content, enamel layer adhesive force does not promote 120% than not adding pore creating material.Data are seen accompanying drawing.

The present invention produces enamel strong adhesion, the fiery lid of blocking-up complex-shaped, that elevated temperature strength is high, with low cost by adopting powder metallurgical technique, has solved the key technology difficult problem that enamel combines with powder metallurgy.Adopt the present invention can successfully utilize the advantage of powder metallurgy to produce blocking-up fire lid, integrated cost can descend 40%.

Description of drawings

Fig. 1 is complete decomposition temperature figure of the present invention.

Fig. 2 tries hard to for the demoulding of the present invention.

Fig. 3 is a cost carbon containing spirogram of the present invention.

Fig. 4 is the figure that adheres to of the present invention.

The specific embodiment

Embodiment 1:

Prepare the powder metallurgy raw material by＜100 orders atomizing Fe powder 99.4kg and compounded lubricant (lithium stearate 50%+ stearic acid 42%+ calcium oxalate 8%) 0.6kg, behind the speed mixing 60min with 19～21r/min in clean double cone mixer, be pressed into the powder metallurgical fire cover pressed compact, pressed compact is at 1120 ℃ of sintering 4h, and last enamel is promptly made the iron base powder metallurgical fire cover finished product.

Claims

1, a kind of production technology of iron base powder metallurgical fire cover is characterized in that described technology mainly may further comprise the steps:

Step 1, batching

Adopt＜100 orders atomizing Fe powder and compounded lubricant in no carbon source environment, to be mixed into the powder metallurgy raw material, wherein, the two mass percent of described＜100 orders atomizings Fe powder and compounded lubricant is:＜100 orders Fe powder 99.5% that atomizes, compounded lubricant 0.5%; Described compounded lubricant forms by lithium stearate, stearic acid and calcium oxalate are composite, and three's mass percent is: lithium stearate 50%, and stearic acid 42%, calcium oxalate 8%,

Step 2, mixing

Powder metallurgy raw material speed with 19～21r/min in clean double cone mixer that step 1 prepares is mixed 60min, makes the powder metallurgy compound,

Step 3, compacting

The powder metallurgy compound that step 2 is made is pressed into fire lid pressed compact,

Step 4, sintering

The pressed compact that step 3 is made is at 1120 ℃ of sintering 4h, powder metallurgy sintered blank,

Step 5, the powder metallurgy sintered blank enamel that step 4 is made promptly get iron base powder metallurgical fire cover.