A kind of refractory aggregate and consisting of stainless steel cast paint and preparation method thereof
Technical field
The invention belongs to founding materials technical field, be specifically related to a kind of refractory aggregate and consisting of stainless steel cast paint and preparation method thereof.
Background technology
In recent years, the application of stainless cast steel part is more and more extensive, and casting dimension also keeps the large-scale development, and structure is to complicated development.But, how to ensure that sand casting stainless cast steel part surface quality and dimensional accuracy receive much concern always.Particularly along with stainless steel is in the expansion of the sector applications such as nuclear industry, shipbuilding industry and military project, how to ensure the stainless quality of the sand casting of large scale, labyrinth, especially problem demanding prompt solution.Adopt mold wash to be the effective way ensureing sand casting stainless steel surfaces quality and dimensional accuracy and roughness, and how to optimize the proportioning of mold wash, ensure the anti-stick grittiness of coating and the heat-resisting quantity key that gives full play to of coating effect especially.Therefore, develop a kind of sand casting coating for stainless cast steel part and have vast potential for future development.
At present, for the coating of stainless steel sand casting, be mostly to adopt zirconium English powder, corundum etc. as coating refractory aggregate, resin is as main binding agent, and ethanol as dispersant, then is aided with other auxiliary agents.This kind of coating can play the effect improving surface quality of continuous castings well to general stainless cast steel part, but also there is a lot of limitation.For the coating adopting zirconium English powder as refractory aggregate, anti-burnon effect is better, but cost is higher, and the anti-burnon poor effect of schmigel coating, particularly on larger-size complex structural member, problem is more outstanding.In addition, the intensity under existing coating hot conditions is poor, easily by erosion, causes local scab or is mingled with.
Summary of the invention
For the deficiency that stainless steel sand casting coating in prior art exists, the invention provides a kind of refractory aggregate and consisting of stainless steel cast paint and preparation method thereof, object improves large scale, labyrinth sand casting stainless cast steel part surface quality.
Refractory aggregate of the present invention, be made up of magnesia powder, schmigel and zirconium English powder, its composition according to mass percent is: magnesia powder 45-55%, schmigel 15-20%, zirconium English powder 30-35%, wherein the granularity of magnesia powder and schmigel is 220 orders, and zirconium English Powder Particle Size is 325 orders.
The stainless steel cast paint be made up of above-mentioned refractory aggregate, its composition according to mass percent is: ethanol 60-70%, lithium bentonite 2-3%, Ludox 2-3%, polyvinyl butyral resin 1.5-2.5%, phenolic resins 0.5-1.0%, surplus is refractory aggregate.
The preparation method of described stainless steel cast paint, carries out according to following steps:
Prepare burden according to component ratio, first expanding treatment is carried out to lithium bentonite, lithium bentonite is well dispersed in ethanol, then add refractory aggregate and stir 10 ~ 25min, add Ludox, polyvinyl butyral and phenolic resins successively again, move in High Rotation Speed mixer and stir 30 ~ 50min, control rotating speed is 1800 ~ 2000r/min, obtains stainless steel cast paint.
Compared with prior art, feature of the present invention and beneficial effect are:
The present invention is the major ingredient using magnesia powder as refractory aggregate, allocates a certain proportion of zirconium English powder and schmigel into, forms composite fire aggregate, has good chemical stability; When forming coating, add appropriate binding agent and bentonite, to the requirement cohesive force of binding agent strong, high temperature resistant (1500 ~ 1600 ° of C), therefore select Ludox as the binding agent of this coating, the water content of this Ludox is 78%, and its shared mass fraction in coating is 2-3%, can effectively increase its elevated temperature strength and normal temperature strength, in process of production, the occurrence rate of chemistry and penetration is significantly reduced.
When carrying out sand casting, by high temperature sintering effect during cast, refractory aggregate forms new fire-resistant phase, improve fire resistance and the anti-burnon ability of coating, and adjust the binding agent of coating, form compoiste adhering effect, both ensured to brush dried strength of coating, ensure again the strength of coating when high temperature, thus ensure the surface quality of foundry goods, prevent Paint Falling from causing foundry goods to produce inclusion defect, lithium bentonite has been carried out expanding treatment by manufacture craft, ensure that the suspension stability that coating is good.
Accompanying drawing explanation
Fig. 1 is shape appearance figure after the sand mold cooling in the embodiment of the present invention 1 after high temperature cast;
Wherein (a) is macro morphology figure; B () is partial enlarged drawing;
Fig. 2 is the XRD collection of illustrative plates of the embodiment of the present invention 1 paint coatings after high temperature cast;
Fig. 3 is the ESEM collection of illustrative plates of the paint coatings of the embodiment of the present invention 2 after high temperature cast;
Fig. 4 is the XRD collection of illustrative plates of the embodiment of the present invention 2 paint coatings after high temperature cast;
Fig. 5 is the XRD collection of illustrative plates of the embodiment of the present invention 3 paint coatings after high temperature cast.
Detailed description of the invention
Below in conjunction with specific embodiment, technical scheme of the present invention is described further, below described in be only the preferred embodiments of the present invention, be not limited to the present invention.
Embodiment 1
The refractory aggregate of the present embodiment, be made up of magnesia powder, schmigel and zirconium English powder, its composition according to mass percent is: magnesia powder 45%, schmigel 20%, zirconium English powder 35%, and wherein the granularity of magnesia powder and schmigel is 220 orders, and zirconium English Powder Particle Size is 325 orders.
The stainless steel cast paint be made up of above-mentioned refractory aggregate, its composition according to mass percent is: ethanol 60%, lithium bentonite 3%, Ludox 2%, polyvinyl butyral resin 2.5%, phenolic resins 0.5%, surplus is refractory aggregate.
The preparation method of described stainless steel cast paint, carries out according to following steps:
Prepare burden according to component ratio, first expanding treatment is carried out to lithium bentonite, lithium bentonite is well dispersed in ethanol, then add refractory aggregate and stir 10min, add Ludox, polyvinyl butyral and phenolic resins successively again, move in High Rotation Speed mixer and stir 30min, control rotating speed is 2000r/min, obtains stainless steel cast paint.
By applying coating at mould surface, coating forms three kinds of cenotypes under the pouring temperature of 1500 DEG C, these material good thermal shock stability, and make cast(ing) surface smooth, coating is easily peeled off, and after cast, sand mold as shown in Figure 1; Fig. 2 is the XRD collection of illustrative plates of coating coating after high temperature cast, and by analysis, the cenotype formed in layer has magnesium aluminate spinel, forsterite, residue small amounts magnesium and zirconium English powder, corundum noresidue.
Embodiment 2
The refractory aggregate of the present embodiment, be made up of magnesia powder, schmigel and zirconium English powder, its composition according to mass percent is: magnesia powder 55%, schmigel 15%, zirconium English powder 30%, and wherein the granularity of magnesia powder and schmigel is 220 orders, and zirconium English Powder Particle Size is 325 orders.
The stainless steel cast paint be made up of above-mentioned refractory aggregate, its composition according to mass percent is: ethanol 65%, lithium bentonite 2.5%, Ludox 2.5%, polyvinyl butyral resin 1.5%, phenolic resins 0.8%, surplus is refractory aggregate.
The preparation method of described stainless steel cast paint, carries out according to following steps:
Prepare burden according to component ratio, first expanding treatment is carried out to lithium bentonite, lithium bentonite is well dispersed in ethanol, then add refractory aggregate and stir 15min, add Ludox, polyvinyl butyral and phenolic resins successively again, move in High Rotation Speed mixer and stir 40min, control rotating speed is 1900r/min, obtains stainless steel cast paint.
By applying coating at mould surface, coating is under the pouring temperature of 1600 DEG C, and cool formation two kinds of cenotypes, these material good thermal shock stability, make cast(ing) surface smooth, coating is easily peeled off; Fig. 3 is the ESEM collection of illustrative plates of coating, can find out, coating connects well after high temperature sintering, basic flawless, wherein a small amount of pore is conducive to stainless cooling, and Fig. 4 is the XRD collection of illustrative plates of coating coating after high temperature cast, by analysis, the cenotype formed in layer is magnesium aluminate spinel, and magnesia powder, zirconium English powder have a small amount of residual, and schmigel is without residue.
Embodiment 3
The refractory aggregate of the present embodiment, be made up of magnesia powder, schmigel and zirconium English powder, its composition according to mass percent is: magnesia powder 50%, schmigel 18%, zirconium English powder 32%, and wherein the granularity of magnesia powder and schmigel is 220 orders, and zirconium English Powder Particle Size is 325 orders.
The stainless steel cast paint be made up of above-mentioned refractory aggregate, its composition according to mass percent is: ethanol 70%, lithium bentonite 2%, Ludox 3%, polyvinyl butyral resin 2%, phenolic resins 1.0%, surplus is refractory aggregate.
The preparation method of described stainless steel cast paint, carries out according to following steps:
Prepare burden according to component ratio, first expanding treatment is carried out to lithium bentonite, lithium bentonite is well dispersed in ethanol, then add refractory aggregate and stir 25min, add Ludox, polyvinyl butyral and phenolic resins successively again, move in High Rotation Speed mixer and stir 50min, control rotating speed is 1800r/min, obtains stainless steel cast paint.
By applying coating at mould surface, coating is under the pouring temperature of 1550 DEG C, and cool formation two kinds of cenotypes, these material good thermal shock stability, make cast(ing) surface smooth, coating is easily peeled off; Fig. 5 is the XRD collection of illustrative plates of coating coating after high temperature cast, and by analysis, the cenotype formed in coating is magnesium aluminate spinel, and magnesia powder, zirconium English powder and schmigel all have residual.This thick and large casting is complex-shaped, uses other kind coating easily to produce thermal center, but after the stainless steel cast paint of coating the present embodiment, only there is a small amount of scab at thermal center place, and the coating adhered to sinters, raps namely peelable with hammer.