How to check the quality of refractory bricks visually?

1. Size check

(1) The inspection of dimensions shall be carried out according to the provisions of the order drawings.

(2) When measuring, the zero point of the steel ruler must be aligned with the edge of the product, and a steel tape measure and a steel ruler can be used. When measuring the inner and outer diameter of the product, use a tool caliper.

(3) For general products (except for special regulations), the size of the middle 1/3 of each side of the product shall prevail.

(4) The measurement of the opposite sides of the product is based on the difference between the opposite sides of the same size of the product. The measurement of the relative side difference between the diameter of the product and the mother is based on the measurement of the difference between the long and short axes of the same child or female mouth of the product.

(5) Where the tolerance value is expressed as a percentage, the value should be calculated to the whole number, and the calculation to one digit after the decimal point is carried out in accordance with the "Rule of Rounding of Numerical Values" (GB8170-87).

2. Inspection of the melt hole

(1) When checking the molten hole, it is allowed to tap the molten cavity and the obvious discoloration part on the surface of the product due to low melting with a small metal hammer, and then measure the maximum diameter of the molten hole with a steel ruler.

(2) Cavities caused by foreign organic inclusions such as wood chips, sludge, cloth, etc. are also inspected according to the inspection method for molten holes, but the allowable value is not greater than 1 times the value of the molten hole of the product (for example: the amount of the molten hole The value is specified as 8mm, the value of the cavity is allowed to be no more than 16mm).

3. Inspection of missing corners and edges

(1) For the inspection of missing corners and the depth of missing edges, use specially manufactured goniometers and edge detectors that can be tightly fitted on the edges and corners of the product and have a scale that slides in the specified direction.

(2) For the depth of missing corners, for right-angle products, use a cube-shaped goniometer to measure along the diagonal direction of the center of the cube; for non-right-angle products, use a Mitsubishi-shaped goniometer to measure along the direction of the centerline of the Mitsubishi body .

(3) The depth of the missing edge, measure the deepest part of the missing edge along the direction of the bisector of the angle between the two sides of the product. For those with a length limit, measure the full length of the missing edge at the same time.

(4) When missing corners and missing edges are connected, check them separately. The missing edge of the missing corner part is not calculated as missing edge, that is, the missing corner part is inspected according to the missing corner regulations, and the missing edge part is inspected according to the missing edge regulations.

(5) Except for special provisions, all missing corners and edges with a depth greater than 3mm to the standard allowable value limit shall be included in the calculation. The missing corners and edges with a depth of 3mm and less than 3mm are not considered as missing corners and missing edges.

4. Inspection of cracks

(1) For the inspection of cracks, use a steel ruler with a scale of 0.5 mm and a steel wire with a diameter equal to the measured crack width (for example, 0.1, 0.25, 0.5, 1.0 mm).

(2) When checking for cracks, insert the steel wire into the widest part of the crack naturally, but not where the particles are visible to the naked eye. For any crack that cannot be inserted by 0.25mm steel wire, its width is expressed as <0.25mm; for any crack that can be inserted by 0.25mm steel wire but cannot be inserted by 0.5mm steel wire, its width is expressed as 0.26~0.5mm
show; and so on.

(3) If the crack is not in a straight line, it can be measured by fractional line segments, and the sum of the lengths of each line segment is the total length of the crack. Cracks (including unrestricted cracks) with discontinuities in the middle and discontinuous distances greater than 5mm are considered as one crack, and their lengths are calculated together, except for cracks in cross and parallel directions.

(4) Cracks across the edge, unless otherwise specified, shall be calculated according to the continuous length. A crack spanning both the working face and the non-working face at the same time shall be assessed according to the working face (for example, a certain standard stipulates that the width is 0.26~0.5mm). If the crack crosses the working face and the non-working face at the same time, the continuous length shall be assessed according to the working face and shall not be greater than 30mm). Cracks that cross two edges at the corners, if they do not exceed the numerical range specified by the missing corners, are not calculated as crossing two edges. All cracks that are not restricted in the standard are not restricted by the cross-edge, and are not inspected.

(5) Surfaces with grooves and tongues are calculated as one surface, except for casting bricks; surfaces with through holes are calculated as two surfaces.

(6) Thin and long cracks formed due to improper cooling are quenching cracks (explosion) and should be treated as unqualified products.

(7) Where a number of cracks form a closed curve, it is a network crack. When calculating the length of the mesh crack, the full length of the periphery shall prevail. Where more than one crack intersects, it is a cross crack. When calculating the number of intersecting cracks, the linear cracks passing through the intersection are mainly used.

(8) Edges with an angle greater than 120° shall not be counted as edges, and faces with dimensions less than 20mm wide shall not be counted as faces, except for casting bricks.

5. Distorted inspection

(1) The twist is checked with a feeler gauge made of sheet metal. The width of the feeler gauge is 10mm, and the thickness is 0.1mm larger than the allowable limit specified by the standard (for example: 1.6, 2.1, 2.6, 3.1, 3.6mm, etc.).

(2) When checking for distortion, place the inspected surface of the product on a flat plate (the area of ​​the plate should be larger than the inspected surface of the product) and keep it naturally stable. Then, insert the feeler gauge smoothly along the board surface into the maximum gap formed by the flat plate and the product, and those whose insertion depth of the feeler gauge does not exceed 10mm is qualified.

(3) The indentation is checked by the twist method.

6. Inspection of the tilt of the end plane

(1) To check the inclination of the end plane, use a right-angle steel ruler with a side length of 220mm*220mm, and a metal feeler gauge with a width of 5mm and a thickness of 0.1mm larger than the allowable limit specified in the standard (for example, check the inclination of the end plane of 2.0mm). , use a feeler gauge with a thickness of 2.1mm).

(2) During inspection, one side of the right-angle steel ruler is in close contact with the longitudinal surface of the product, while the other side of the right-angle steel ruler is close to the end, and then the feeler gauge is smoothed along the gap formed between the right-angle steel ruler and the end. If the feeler gauge cannot be inserted, it is qualified.

7. Inspection of slag corrosion

(1) Any glass-like deposits due to the combination of the ash of the fuel and the surface of the product during firing; the molten discoloration caused by the erosion of the surface of the product due to chemical changes between other impurities and the surface of the product, collectively referred to as slag eclipse.

(2) After processing and grinding, the products without obvious pitting and erosion shall not be counted as slag erosion.

8. Inspection of raw burning products

(1) For products produced with the same raw materials and the same process, the appearance and color of the products after firing are significantly different from those of normal production products, the size expansion and contraction are insufficient, and the particles are not significantly broken when the section is opened, the firing condition of the products should be checked.

(2) Judgment of raw burning products shall be subject to the identification of physical properties.

(3) Raw burning products should be treated as unqualified products.

9. Section inspection

(1) The layered structure of the product due to molding and the layered structure with gaps on the cross-section is the cross-sectional spallation. The section of the product is obtained by hammering and chisel in the longitudinal direction perpendicular to the forming and pressing surface of the product. The inspection of cross-section spalling is carried out according to the fourth article.

(2) Local significant discoloration caused by firing of self-made products, such as black and red, is a black heart or a red heart. Products with black hearts or red hearts are judged as unqualified products (except for high alumina bricks with Al2O3 ≥ 75% due to high temperature and atmosphere).

10. Check the shape of plug bricks and cast bricks

(1) To check the regularity of the shape of the plug brick, use the matching sprue brick, place the plug brick on the matching sprue brick, press it lightly with your hand, and make the plug brick rotate around the central axis. Where the wear scars on the plug bricks are in an uninterrupted continuous ring, it is a qualified product.

(2) To check the regularity of the shape of the casting brick, use the matching plug brick, put the matching plug brick on the casting brick, press it lightly with your hand, and make the plug brick rotate around the central axis. Those with an uninterrupted and continuous ring of wear marks on the cast bricks are qualified products.

11. Inspection of working face and non-working face

(1) Where the drawing specifies the working face on the product, it shall be checked according to the working face specified in the standard; the non-working face shall be checked according to the unspecified working face.

(2) The edges and corners connected to the working face shall be inspected according to the regulations of the working face.