Depreciation and interest on steel
2022-10-27
Iron and steel equipment investment is an important feature of the iron and steel industry. From the global perspective, according to statistics: in addition to Japan's rapid depreciation, the United States, Europe, South Korea and China's iron and steel enterprises generally adopt normal depreciation, while Russia's depreciation rate is the slowest. But what about depreciation and interest on steel? Here is a detailed explanation of steel depreciation and interest.
Depreciation and interest on steel:
As the steel industry is a capital-intensive industry, the asset-liability ratio of Chinese steel enterprises is generally above 50%, so the change of national monetary policy will seriously affect the financial expenses of steel enterprises.
The general rule of carbon steel can be approximated as the higher the carbon content, the higher the hardness, but the hardness decreases with the increase of the carbon content. The hardness of iron and steel material mainly depends on the chemical composition of the material (steel), the hardness of the high carbon content; And the heat treatment state.
Iron and steel contain a small amount of alloying elements and impurities of iron-carbon alloy, according to the carbon content can be divided into:
Pig iron -- contains 2.0 to 4.5% C
Steel -- Contains 0.05 ~ 2.0% C
Wrought iron -- contains less than 0.05% C
The amount of carbon is the main criterion to distinguish steel. The carbon content of pig iron is more than 2.0%; The carbon content of steel is less than 2.0%. Pig iron is high in carbon, hard and brittle, and almost plastic.
But it is not right to use carbon content as an indication of hardness, which is related to the internal structure. Such as ferrite, austenite, cementite, pearlite, etc. In practical application, if high hardness is needed, then it must be through carburizing quenching or nitriding and other heat treatment. Because carbon content is only an important factor affecting hardness, not the only absolute factor. It has to do with the internal structure. Diamond is made of carbon and has the highest hardness.
l Roundness The diameter of rolled material with circular section, such as round steel and round steel pipe, varies in all directions.
The geometrical shape of the cross section of the rolled material is skewed and uneven. Such as six angles of the six sides of the unequal Angle, Angle Angle, steel torsion, etc.
The thickness of each part of the steel plate (or steel belt) is not the same. Some sides are thick and the middle is thin, some sides are thin and the middle is thick, and some head and tail difference exceeds the requirement.
4 Bending rolled parts in the direction of length or width is not straight, curved.
The LENGTH DIRECTION OF THE SICKLE BEND steel plate (or steel strip) is bent to one side in the horizontal plane.
6. The curved steel plate (or steel strip) has high and low waves in the direction of length and width at the same time, making it a "ladybird shape" or "boat shape".
7. The strip rolling piece is twisted into a spiral along the longitudinal axis.
8 out of square, out of moment square, rectangular section of the material opposite side is not equal or the diagonal of the section is not equal.
9. The pull marks (scratches) are in the shape of straight grooves, and the naked eye can see that the bottom of the grooves is distributed in the part or the whole length of the steel.
10 The crack is generally linear, sometimes Y shape, and the drawing direction is consistent, but there are also other directions, the general opening is acute Angle.
ll heavy skin (scar) surface in the form of tongue or fish scale sheet warped sheet: one is connected with the body of the steel, and folded to the surface is not easy to fall off; The other is not connected to the body of the steel, but bonded to the surface is easy to fall off.
The folded steel surface overlaps locally and has obvious folds.
13 Rust generated on the surface of rust, its color from apricot yellow to black red, after rust removal, serious rust hemp.
14 Hair grain surface hair grain is the depth is very shallow, the width is very small hair fine grain, generally along the rolling direction to form fine grain.
There is local obvious metal structure separation on the section of 15 layered steel, and it is divided into 2 ~ 3 layers when serious, and there are visible inclusions between the layers.
16. The surface of the bubble is irregularly distributed as a circular convex hull, and its outer edge is relatively smooth. Most of them are bulging, and some do not bulge and after pickling smooth surface shiny, its shear section has stratification.
17 Pitting (pitting surface) surface presents local or continuous pieces of rough surface, distributed with different shapes, different sizes of pits, serious similar to orange peel, larger and deeper than pitting spots.
After annealing, the steel plate (or steel strip) shows light yellow, dark brown, light blue, dark blue or bright gray on the surface.
19 roll printing surface has a strip or sheet of periodic roll printing, the embossing part is brighter, and there is no obvious convex and concave feeling.
The noncompactness of loose steel. After acid erosion, the sections expanded into many caves, according to their distribution can be divided into: generally loose, loose center.
Uneven distribution of chemical composition and non-metallic inclusions in 2l segregated steel. According to its form, it can be divided into dendritic, square, punctate segregation and inverse segregation.
22 The shrinkage cavity remains in the center of the transverse acid leaching test sheet, showing an irregular cavity or crack. Holes or cracks are often left with foreign impurities.
23 Non-metallic inclusions in the transverse acid test sheet to see some non-metallic luster, gray, beige and dark gray color, is the steel residual oxide, sulfide, silicate, etc.
Some metallic salts with metallic luster obviously different from the base metal were found on the transverse low-magnification test pieces.
When the microstructure after erosion is observed by overfiring, decarbonized microstructure is often seen on the matrix metal around the net-like oxide, while other metals such as copper and its alloys have copper oxide extending into the sample along the grain boundary in a net-like or punctured shape.
It is a type of internal rupture in steel. On the longitudinal fracture of the steel, round or oval silver-white spots appear, and on the transverse section after polishing and etching, they appear as elongated cracks, sometimes radiating, sometimes parallel to the direction of deformation or irregular distribution.
27 grain coarse acid leaching test fragment mouth has a strong metallic luster.
The phenomenon that the carbon content of the surface layer of decarbonized steel is lower than that of the inner layer is called decarbonization. The fully decarbonized layer means that the surface of the steel is all ferrite because of decarbonization. Partial decarbonization refers to the tissue where the carbon content of the steel is not reduced after the full decarbonization layer.
Depreciation and interest on steel:
As the steel industry is a capital-intensive industry, the asset-liability ratio of Chinese steel enterprises is generally above 50%, so the change of national monetary policy will seriously affect the financial expenses of steel enterprises.
The general rule of carbon steel can be approximated as the higher the carbon content, the higher the hardness, but the hardness decreases with the increase of the carbon content. The hardness of iron and steel material mainly depends on the chemical composition of the material (steel), the hardness of the high carbon content; And the heat treatment state.
Iron and steel contain a small amount of alloying elements and impurities of iron-carbon alloy, according to the carbon content can be divided into:
Pig iron -- contains 2.0 to 4.5% C
Steel -- Contains 0.05 ~ 2.0% C
Wrought iron -- contains less than 0.05% C
The amount of carbon is the main criterion to distinguish steel. The carbon content of pig iron is more than 2.0%; The carbon content of steel is less than 2.0%. Pig iron is high in carbon, hard and brittle, and almost plastic.
But it is not right to use carbon content as an indication of hardness, which is related to the internal structure. Such as ferrite, austenite, cementite, pearlite, etc. In practical application, if high hardness is needed, then it must be through carburizing quenching or nitriding and other heat treatment. Because carbon content is only an important factor affecting hardness, not the only absolute factor. It has to do with the internal structure. Diamond is made of carbon and has the highest hardness.
l Roundness The diameter of rolled material with circular section, such as round steel and round steel pipe, varies in all directions.
The geometrical shape of the cross section of the rolled material is skewed and uneven. Such as six angles of the six sides of the unequal Angle, Angle Angle, steel torsion, etc.
The thickness of each part of the steel plate (or steel belt) is not the same. Some sides are thick and the middle is thin, some sides are thin and the middle is thick, and some head and tail difference exceeds the requirement.
4 Bending rolled parts in the direction of length or width is not straight, curved.
The LENGTH DIRECTION OF THE SICKLE BEND steel plate (or steel strip) is bent to one side in the horizontal plane.
6. The curved steel plate (or steel strip) has high and low waves in the direction of length and width at the same time, making it a "ladybird shape" or "boat shape".
7. The strip rolling piece is twisted into a spiral along the longitudinal axis.
8 out of square, out of moment square, rectangular section of the material opposite side is not equal or the diagonal of the section is not equal.
9. The pull marks (scratches) are in the shape of straight grooves, and the naked eye can see that the bottom of the grooves is distributed in the part or the whole length of the steel.
10 The crack is generally linear, sometimes Y shape, and the drawing direction is consistent, but there are also other directions, the general opening is acute Angle.
ll heavy skin (scar) surface in the form of tongue or fish scale sheet warped sheet: one is connected with the body of the steel, and folded to the surface is not easy to fall off; The other is not connected to the body of the steel, but bonded to the surface is easy to fall off.
The folded steel surface overlaps locally and has obvious folds.
13 Rust generated on the surface of rust, its color from apricot yellow to black red, after rust removal, serious rust hemp.
14 Hair grain surface hair grain is the depth is very shallow, the width is very small hair fine grain, generally along the rolling direction to form fine grain.
There is local obvious metal structure separation on the section of 15 layered steel, and it is divided into 2 ~ 3 layers when serious, and there are visible inclusions between the layers.
16. The surface of the bubble is irregularly distributed as a circular convex hull, and its outer edge is relatively smooth. Most of them are bulging, and some do not bulge and after pickling smooth surface shiny, its shear section has stratification.
17 Pitting (pitting surface) surface presents local or continuous pieces of rough surface, distributed with different shapes, different sizes of pits, serious similar to orange peel, larger and deeper than pitting spots.
After annealing, the steel plate (or steel strip) shows light yellow, dark brown, light blue, dark blue or bright gray on the surface.
19 roll printing surface has a strip or sheet of periodic roll printing, the embossing part is brighter, and there is no obvious convex and concave feeling.
The noncompactness of loose steel. After acid erosion, the sections expanded into many caves, according to their distribution can be divided into: generally loose, loose center.
Uneven distribution of chemical composition and non-metallic inclusions in 2l segregated steel. According to its form, it can be divided into dendritic, square, punctate segregation and inverse segregation.
22 The shrinkage cavity remains in the center of the transverse acid leaching test sheet, showing an irregular cavity or crack. Holes or cracks are often left with foreign impurities.
23 Non-metallic inclusions in the transverse acid test sheet to see some non-metallic luster, gray, beige and dark gray color, is the steel residual oxide, sulfide, silicate, etc.
Some metallic salts with metallic luster obviously different from the base metal were found on the transverse low-magnification test pieces.
When the microstructure after erosion is observed by overfiring, decarbonized microstructure is often seen on the matrix metal around the net-like oxide, while other metals such as copper and its alloys have copper oxide extending into the sample along the grain boundary in a net-like or punctured shape.
It is a type of internal rupture in steel. On the longitudinal fracture of the steel, round or oval silver-white spots appear, and on the transverse section after polishing and etching, they appear as elongated cracks, sometimes radiating, sometimes parallel to the direction of deformation or irregular distribution.
27 grain coarse acid leaching test fragment mouth has a strong metallic luster.
The phenomenon that the carbon content of the surface layer of decarbonized steel is lower than that of the inner layer is called decarbonization. The fully decarbonized layer means that the surface of the steel is all ferrite because of decarbonization. Partial decarbonization refers to the tissue where the carbon content of the steel is not reduced after the full decarbonization layer.
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