Development of VOD ladle lining refractories

 Magnesia-chrome brick was first used in VOD ladle lining because of its excellent slag resistance. However, under intermittent operation of VOD ladle, magnesia-Chrome brick is easy to produce spalling damage and poor thermal shock resistance. Because of the environmental protection of hexavalent chromium, the use of chromium-containing refractories is more and more restricted. At present, domestic stainless steel steel mills have rarely used magnesia-chrome brick.

In Europe, VOD ladle lining is mostly made of (magnesium) dolomite bricks. Compared with magnesia-Chrome brick, dolomite brick has good thermal shock resistance due to its high temperature flexibility. Most VOD ladles in China use magnesium-calcium bricks fired at high temperature. Although magnesium-calcium brick has the function of purifying molten steel and has better thermal shock resistance than magnesium-chromium brick, the content of CaO in the brick reduces slag erosion resistance under the condition that the slag composition of VOD ladle varies greatly and is mainly acidic slag. Due to the hydration problem, magnesium-calcium brick is not suitable for intermittent production, and the management of storage, use and other aspects puts forward very high requirements.

In the smelting of low carbon and ultra-low carbon stainless steel, stainless steel plants are reluctant to use magnesium carbon brick for fear that the liquid steel may be carburized by using magnesium carbon bricks in VOD ladle. In fact, these problems can be minimized by using low-carbon magnesium-carbon bricks. Although low carbonization tends to reduce the thermal shock resistance, the bricks with excellent thermal shock resistance can be developed by selecting the best amount of special asphalt and antioxidant.

Article Source:Development of VOD ladle lining refractories
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

Construction method of refractory casting material

Chinafirebrick provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, Magnesia Carbon Brick, clay refractory bricks and other refractory.

Castable lining construction
1, refractory castable construction
2, castable stir
Mixing time should be no less than 5 minutes. Operation to use a forced mixer, stirring should first dry mixing, then add 80% solvent stirring, and then depending on the degree of wet and dry construction and specific parts of the request, and then slowly add the remaining solvent until the appropriate working consistency until. In ensuring the construction performance of the premise, the amount of solvent should be less good.

Refractory castables should be used in the whole bag, stir well castable must be used within 30 minutes. In the high temperature drying of the operating environment but also to shorten the time. Has been initial coagulation or agglomeration of refractory castables shall not be used, do not add solvent stirring and then use.
3, vibrating
Refractory castable pouring into the template should be immediately vibrated with a vibrator, each layer height is less than 300 mm, vibration spacing to 2500mm is appropriate.
Vibration, try to avoid touching the anchor, shall not damage the insulation layer, not in the same position for a long time and re-vibration. Casting surface after the slurry should be slowly out of the vibrator to avoid casting material and the emergence of isolated phenomenon. The cast body after pouring can no longer be pressed and shocked before solidification.
4, pouring and expansion joints
Large area construction pouring to block construction. Each casting area to 1.5m2 is appropriate (with a mixing amount of synchronization.) Expansion joints required to stay (usually in the pouring time to consider), shall not be missed. In the kiln, the expansion joints in the decomposition furnace are located in the axial ring, not less than 4, to aluminum silicate fiber felt as the material.
5, maintenance and mold release inspection
After the surface of the castable material is dried, it is necessary to carry out the necessary maintenance according to the construction and maintenance requirements, especially the castable for water conservation, and sprinkle it regularly to keep the surface moist. After the final pouring of refractory raw material can be removed side mold to continue to sprinkler conservation, but the load-bearing template to be the strength of 70% before stripping.
After the removal of the template should be timely on the casting inspection, found honeycomb, peeling and empty quality problems such as timely processing and repair. When the problem is serious, the defect should be chiseled to expose the anchor, and then use the homogeneous pound to fill the material to continue conservation. It is forbidden to cover up the problem with mud.
6, composite lining construction
On the fire-resistant insulation composite lining to be layered construction, is strictly prohibited mixed layer of slurry construction, insulation materials (such as silicon calcium board, silicon aluminum, asbestos or slag cotton, etc.) should be sprayed with waterproof moisture-proof refractory castable. There have many refractory news and refractory products information on web. You can read more refractory products and know more refractory materials information. Because our website has many kinds of refractory news and industry news. what's more ,you can know more kinds of refractory information from our website.
Article Source: Refractory raw materials
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/

Construction regulations of unshaped casting materials

Refractory Casting materials manufacturers show that: because of the many types of castables, most of which customers on the infinitely castable in this area of knowledge is relatively lacking, in order to improve the construction efficiency and to avoid errors. There have many refractory news and refractory products information on web. You can read more refractory products and know more refractory materials information. Because our website has many kinds of refractory news and industry news. what's more ,you can know more kinds of refractory information from our website.

First, the inspection before construction

Inspection before construction should be carried out strictly, including the following
1, clear the refractory castable equipment, the appearance of the structure and clean
2, the construction equipment of the intact, vibrating tools must have a good use of pieces
3, the process of leaving the hole
4, anchor type, size, layout and welding quality, metal anchors must be done for expansion compensation
5, around the refractory fire brick insulation layer to do a good job of cast water loss (glue) preventive measures
6, the packaging of the castable and the date of the factory, and pre-test to check whether the failure
7, pouring procedures
8, the implementation of the construction process formula
9, the construction of water quality must meet the quality of drinking water

The above inspection should be handled after the failure to be qualified before the construction, expired failure of the refractory raw material shall not be used.
Second, the construction template.

Available from steel or hardwood (bamboo). Template to have sufficient strength, good rigidity, do not take shape, do not shift, do not leak pulp. Steel mold to use mold, wood template to brush waterproof paint. Reuse of wood before cleaning and then use. Chinafirebrick provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, Magnesia Carbon Brick, clay refractory bricks and other refractory.

Article Source: Refractory raw materials
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/