Checking work of castable material before construction

Construction of casting material before should strictly check the following:

1, castable material construction is made of steel or hard wood templates are available. The template must be of adequate strength, good rigidity, not out of shape, do not shift, no leakage of slurry. Steel template to mold release agent. Wood template to brush waterproofpaint. The repeated use of the template to cleaning, painting can be used.

2 water, pouring material should be strictly according to the manual control, shall not exceed the limit. Under the premise of ensuring the construction performance, the amount of water should be less than.

3,  castable refractory mixing time should not less than 5 minutes. The operation to the use of forced mixer. Mixing should first dry mix, then add 80% dosage of water mixing, and then depending on the extent of wet and dry, gently stir until the remaining water, obtaining suitable work consistency so far. Stirring casting materialdifferent should first mixer clean.

4, pouring material must use the whole barrel bag full of. Stirring casting material generally good must be used within 30 minutes. Drying at high temperature working environment should be appropriate to shorten this time. Already first castable coagulation even caking not poured into the mould, nor of mixing water reuse.

5, if the project inspection unqualified should deal with qualified rear can construction. Expired materials shall not be used. Construction of castable to ensure that no power outages not interrupted construction.

The second quarter of Henan refractory products quality supervision and inspection results

2014 for the second quarter of Quality and Technical Supervision, Henan Province, therefractory product quality supervision and inspection of the province, were taken Zhengzhou, Luoyang, Xuchang, Nanyang four provincial cities and Gongyi a straight pipe county (city) 53 companies production of 89 batches of refractory products, a batch of the product does not meet the standard requirements.

This inspection according to GB / T 2988-2012 “aluminum brick”, YB / T 5106-2009 “clay firebrick”, GB / T 2275-2007 “magnesia and magnesia bricks“, YB / T 5049-2009 “skateboard brick” and other refractory product standards and product quality requirements express, the chemical composition of the product mass fraction, melt index, apparent porosity, bulk density, true density, apparent density, room temperature flexural strength, compressive strength at room temperature, heating permanent change, load softening start temperature, refractoriness,high temperature flexural strength, thermal conductivity, thermal expansion, thermal shock resistance and abrasion resistance at room temperature, such as 17 projects have been tested.

After sampling, a company of a batch Galaxy MgO-C (Specifications Model MT-14C production date 2014-2-28) does not meet the standard requirements, related to the carbon content of the project. Henan Province Quality and Technical Supervision said it had instructed the relevant provincial cities, straight county (city) quality and technical supervision departments in accordance with relevant laws and regulations of this inspection in substandard products and production companies and the law.

Refractory castable using validity period and size selection

一、Using effective period

Need watering tie with monolithic refractories, such as high temperature cement, refractory plastic, refractory castable, etc., must be checked before use its expiry date. Exceeds the material period, its performance will decline.

Unpacking refractory castable pocket, be sure to carefully view the manufacture date on the bag. Such as alumina cement shelf life of 3 to 6 months, cement vulnerable to air humidity during storage and transport and curdle, must be strictly checked.

Refractory soft plastic blank group, due to solidification into lumps, you can not using.

二、Granularity refractory castable

Refractory castable granularity shape, strength, size and composition, the quality of the masonry has a very important influence.

Check granularity shape, generally use visual methods. Such as knotted crucible induction furnace lining was prismatic granularity best with sharp corners. Check granularity intensity can be struck with a wooden hammer, watching the situation to determine its smash.

Check the size and composition of the particle size, the use of screening method. Sieving is carried out in the test chamber, which can be measured by the percentage of various particle size of the composition.

First check pattern according to the technical requirements of the stove on, pay attention to the size of the maximum size limits, and secondly to fire clay should be careful not lost too many fine parts, so as not to reduce its masonry performance.

Reason of casting refractory material for high temperature resistance

Casting refractory material, its main characteristic is high early strength, 3-7 days maximum compressive strength can reach more than 30MPa, and the disadvantage is the volume stability of temperature difference, the intensity decrease, the maximum fall by up to 40%, so the requirements for compressive strength must meet the design requirements and national standards.

The temperature reduces the strength of the main factors are: Casting reaches a certain temperature with low calcium and high alumina cement fireproof material in the heating furnace heating process (350 DEG C), dehydration, transformation of the hydrate started hydrate of cement stone structure, compactness and strength decreased, the volume of pouring material change, this time to the strength of castable the lowest point, after stabilizing. With the heating temperature up to 1100 DEG C, cement stone gradually sintering, casting crystalline refractory mullite crystal transformation. With the temperature rising, mullite crystal growing, a glass matrix liquid phase pouring material, forming a high temperature sintering shape, strength increase. At about 1300 DEG C, casting refractory material strength can reach more than 60MPa, a remarkable characteristic of refractory materials under high temperature condition for this is pouring.

Several suggestions of refractories in China exported to Japan

As people’s awareness of environmental protection and the implementation, some new environmental regulations in the future, not only the requirements of zero discharge of waste refractory material itself, but also the requirements of the refractory material used in the process, give full play to the refractory effect at the same time, produces no environmental pollution and harm to human health of hazardous substances. For example, some Japanese well-known large companies (including Mitsui shipbuilding and Nippon Steel etc.) are actively involved in the development of the manufacturing technology of waste incineration furnace. In order to reduce the dioxin content in garbage incineration furnace gas by discharge of, is now generally by increasing furnace burning temperature method to solve the. Because the furnace burning temperature increase, erosion rate of refractory materials to accelerate, make the refractory shorten service life. The best way to increase the burning furnace refractory life, aluminum chrome refractories is the use of high chromium content. But the use of aluminum chrome refractories will remain six chromium harmful in the slag and waste refractory material, resulting in the pollution of the environment. Therefore, at present Japan are developing new refractories for furnace burning.

Add a few suggestions of refractories in China export to Japan, because Japan’s sustained economic recession since 1995 and the appreciation of the yen, the Japanese iron and steel enterprises to reduce production costs, improve the competitiveness of steel products in the international market, the major steel companies have increased the volume of imports of refractories, refractories so Japanese imports surge. 1997 has reached 167204t, which imports from China accounted for the total amount of 72322t, the import of refractory 43.3% in Japan

The reasons of refractory brick collapse in the process of use

For refractory brick, we should not feel strange. With the progress of society, the application of refractory brick is more and more widely. Refractory brick appear collapse phenomenon, in the actual use so, what causes it; following the Xinmi Changxing refractory material factory is simple to give you introduced the refractory brick collapse reason

Refractory brick 1, red hot suddenly quenched with water to produce rupture and fall.

The 2 stage, oven heating rate master is not strict, temperature rise too fast, causing severe dehydration, masonry and damage due to expansion and shrinkage.

3 build stove masonry to expand stay insufficient, cracked and falling temperature after expansion.

4, the ash accumulation system, most of the metal salt corrosion of the refractory brick, embitterment of vanadium and nickel will penetrate into the refractory brick falling off caused by.

5 when the liquefied gas, heating, air flow ratio is undeserved, cause furnace blasting and vibration split off.

6, poor air flow furnace, flame directly flush furnace brick, the furnace brick thinning after a serious fall.

7, the operation too, lifting furnace temperature pressure to balance, it is strictly prohibited to excessive temperature and pressure, avoid the sharp rise in the drop, because the temperature of each layer of brick always lags behind the furnace temperature, the more rely on the outer temperature changes more slowly, if drastic changes in a short time the temperature of the furnace, brick layer between refractory brick and brick joints rupture is caused due to temperature difference is too large to generate huge internal stress. Furnace pressure will cause the sudden change, refractory brick for each layer of gas pressure can’t balance, pressure increasing and destroyed, may cause the whole refractory lining of furnace temperature fluctuation pressure serious collapse.

The role of boron carbide in castable refractory

Boron carbide refractory castable is very important to a substance; it can play a role in anti-compounds. Today, we look at the technical level to explain the important role of boron in castable.

Carbonation can make refractory castable product densification, suppression of carbonaceous refractory castable carbon compounds, but at the time of 1000 ℃ ~ 1250 ℃, Al2O3 and B2O3 reacts 9Al2O3 • columnar crystals 2B2O3, located in refractory castable the cracks in the matrix and thus decrease the porosity, temperature mobilize intensity, and the resulting 9Al2O3 • 2B2O3 crystals, volume expansion, can heal the volume is reduced, diminishing cracks.

Castable field of application of different specifications are not the same. We have to consider many factors, general used in firing big skateboard, Al2O3-SiC-C iron trough castable, as well as some high-speed non-burning carbonaceous refractory castable and Al2O3-C refractory castable, MgO-Crefractory interstitial castable general do not, due to the intervention of the elements boron affect the refractory castable using the furnace.

You can use Sic powder, metallic Al powder, metallic Si powder, ZrB6 from anti compounds such as replacing utility, aluminum casting material can be a little boric acid substitution, but pay special attention to the amount of manipulation.

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