In our country, the purpose classification of steel is used as the basis for the classification of expression methods:
1) Carbon structural steel:
Representation method: Q + number + (quality grade symbol) + (deoxidation method symbol) + (special purpose symbol)
①The steel number is prefixed with "Q", which represents the yield point of the steel;
②The number after "Q" indicates the yield point value, and the unit is MPa. For example, Q235 represents a carbon structural steel with a yield point (σs) of 235 MPa;
③ If necessary, symbols indicating the quality grade and deoxidation method can be marked after the steel number.
The quality grade symbols are A, B, C, and D respectively.
Deoxidation method symbols: F represents boiling steel; b represents semi-killed steel; Z represents killed steel; TZ represents special killed steel. Killed steel may not be marked with symbols, that is, both Z and TZ may be unmarked. For example, Q235-AF represents Grade A boiling steel.
Special-purpose carbon steel: such as bridge steel, marine steel, etc., basically use the representation method of carbon structural steel, but a letter indicating the purpose is appended to the end of the steel number.
2) High quality carbon structural steel
Representation method: number + (element symbol) + (deoxygenation method symbol) + (special-purpose symbol)
①The two digits at the beginning of the steel number indicate the carbon content of the steel, expressed as a few ten thousandths of the average carbon content. For example, for steel with an average carbon content of 0.45%, the steel number is "45". It is not a sequential number, so it cannot be read as 45 gauge steel.
② For high-quality carbon structural steel with high manganese content, the manganese element should be marked, such as 50Mn.
③ Boiling steel, semi-killed steel and special-purpose high-quality carbon structural steel should be specially marked at the end of the steel number. For example, semi-killed steel with an average carbon content of 0.1% has a steel number of 10b.
3) Carbon tool steel
Representation method: letter T + number + (element symbol) + (quality grade symbol)
① The steel number is marked with "T" to avoid confusion with other steel types.
② ②The number in the steel number indicates the carbon content, expressed as a few thousandths of the average carbon content. For example, "T8" means an average carbon content of 0.8%.
③ ③ For those with higher manganese content, "Mn" will be marked at the end of the steel number, such as "T8Mn".
④ ④ The phosphorus and sulfur content of high-grade high-quality carbon tool steel is lower than that of ordinary high-quality carbon tool steel. The letter "A" is added at the end of the steel number to indicate the difference, such as "T8MnA".
⑤ 4) Free cutting steel
⑥ Representation method: letter Y + number + (element symbol)
⑦ ①The steel number is marked with "Y" to distinguish it from high-quality carbon structural steel.
⑧ ②The number after the letter "Y" indicates the carbon content, expressed in ten thousandths of the average carbon content. For example, the steel number of free-cutting steel with an average carbon content of 0.3% is "Y30".
⑨ ③ Those with higher manganese content will also be marked with "Mn" after the steel number, such as "Y40Mn".
⑩ 5) Alloy structural steel
⑪Representation method: (special purpose symbol) + number + main alloy element symbol and number + trace alloy element symbol + (quality grade symbol) + (special purpose symbol)
⑫①The two digits at the beginning of the steel number indicate the carbon content of the steel, expressed as a few ten thousandths of the average carbon content, such as 40Cr.
⑬②The main alloying elements in steel, except for a few micro-alloying elements, are generally expressed in percentages. When the average alloy content is less than 1.5%, the steel number is generally marked with the element symbol instead of the content. However, in special circumstances that may cause confusion, the number "1" can also be marked after the element symbol, such as the steel number. "12CrMoV" and "12Cr1MoV", the former has a chromium content of 0.4-0.6%, the latter has a chromium content of 0.9-1.2%, and the rest of the ingredients are the same. When the average content of alloy elements is ≥1.5%, ≥2.5%, ≥3.5%..., the content should be indicated after the element symbol, which can be expressed as 2, 3, 4... etc. accordingly. For example 18Cr2Ni4WA.
⑭③Alloying elements such as vanadium V, titanium Ti, aluminum AL, boron B, and rare earth RE in steel are all micro-alloying elements. Although the content is very low, they should still be marked in the steel grade. For example, in 20MnVB steel: vanadium is 0.07-0.12% and boron is 0.001-0.005%.
⑮④High-grade high-quality steel should be distinguished from general high-quality steel by adding "A" at the end of the steel number.
⑯⑤Special-purpose alloy structural steel, the steel number is preceded (or suffixed) by a symbol representing the purpose of the steel type. For example, 30CrMnSi steel special for rivets, the steel number is expressed as ML30CrMnSi
⑰6) Low alloy high strength steel
⑱Representation method: (special purpose symbol) + number + main alloy element symbol and number + trace alloy element symbol + (quality grade symbol) + (special purpose symbol)
⑲①The expression method of steel grade is basically the same as that of alloy structural steel.
⑳② For professional low-alloy high-strength steel, the steel number should be indicated at the end. For example, 16Mn steel, the special steel type used for bridges is "16Mnq", the special steel type used for automobile girders is "16MnL", and the special steel type used for pressure vessels is "16MnR".
217) Spring steel
22 Spring steel can be divided into two categories according to its chemical composition: carbon spring steel and alloy spring steel. The steel number is expressed in the way that the former is basically the same as high-quality carbon structural steel, and the latter is basically the same as alloy structural steel.
238) Rolling bearing steel
24 representation method:
25 high carbon chromium bearing steel: letters G+Cr element symbols and numbers
26 carburized bearing steel: letter G + number + main alloy element symbol and number + trace alloy element symbol + (quality grade symbol)
27①The steel number is preceded by the letter "G", which represents rolling bearing steel.
28②The carbon content of high-carbon chromium bearing steel grades is not marked, and the chromium content is expressed in parts per thousand, such as GCr15. The method of expressing the steel grade of carburized bearing steel is basically the same as that of alloy structural steel.
299) Alloy tool steel and high speed tool steel
30① When the average carbon content of the alloy tool steel grade is ≥1.0%, the carbon content is not marked; when the average carbon content is <1.0%, it is expressed in thousandths. For example, Cr12, CrWMn, 9SiCr, 3Cr2W8V.
31②The expression method of alloy element content in steel is basically the same as that of alloy structural steel. However, for alloy tool steel grades with lower chromium content, the chromium content is expressed in parts per thousand, and "0" is added before the number indicating the content so that it can be compared with the general element content expressed in percent. distinguish. For example Cr06.
32③The steel grade of high-speed tool steel generally does not indicate the carbon content, but only indicates the percentage of the average content of various alloying elements. For example, the steel grade of tungsten high-speed steel is expressed as "W18Cr4V". Steel grades marked with the letter "C" indicate that their carbon content is higher than general steel grades without "C". The public account "Mechanical Engineering Literature", a gas station for engineers!
3310) Stainless steel and heat-resistant steel
34①The carbon content in the steel grade is expressed in parts per thousand. For example, the average carbon content of "2Cr13" steel is 0.2%. If the carbon content in the steel is ≤0.03% or ≤0.08%, the steel number will be preceded by "00" and "0" respectively, such as 00Cr17Ni14Mo2, 0Cr18 Ni9, etc. .
35②The main alloying elements in steel are expressed in percentages, while titanium, niobium, zirconium, nitrogen...etc. are marked according to the above-mentioned expression method of microalloying elements in alloy structural steel.
3611) Welding rod steel
37 Its steel number is preceded by the letter "H" to distinguish it from other steel types. For example, the stainless steel welding wire is "H2Cr13", which can be distinguished from the stainless steel "2Cr13".
3812) Silicon steel for electrical purposes
39①The steel number consists of letters and numbers. The letter DR at the beginning of the steel number indicates hot-rolled silicon steel for electrical applications, DW indicates cold-rolled non-oriented silicon steel for electrical applications, and DQ indicates cold-rolled oriented silicon steel for electrical applications.
40②The number after the letter indicates 100 times the iron loss value (W/kg).
41③ If the steel number is added with the letter "G" at the end, it means that it was inspected at a high frequency; if "G" is not added, it means that it was inspected at a frequency of 50 cycles.
42 For example, steel number DW470 indicates that the maximum unit weight iron loss value of cold-rolled non-oriented silicon steel products for electrical purposes at a frequency of 50 Hz is 4.7W/kg.
4313) Pure iron for electricians
44① Its grade consists of the letters "DT" and numbers. "DT" represents pure iron for electricians, and the numbers represent the sequence numbers of different grades, such as DT3.
45②The letters added after the number indicate the electromagnetic performance: A - advanced, E - special grade, C - super, such as DT8A.
46 Common Japanese brands in general and mechanical structural steel plates
472. Common Japanese steel grade expression methods and meanings:
482.1 Japanese steel (JIS series) grades of ordinary structural steel mainly consist of three parts:
49 The first part (indicating material: S〈Steel〉steel, F〈Ferrum〉iron) + the second part (indicating shape, type, use: P〈Plate〉 means plate, T〈Tube〉 means tube, K〈Kogu〉 means Tool, S〈Structure〉 represents structure) + the third part (represents characteristic number, usually the lowest tensile strength) such as:
501) SS400 - the first S represents steel, the second S represents structure, 400 represents the lower limit tensile strength of 400MPa, and the overall represents ordinary structural steel with a tensile strength of 400MPa.
512) SPHC - the first S represents Steel, the second P represents Plate, the third H represents Heat, the fourth C represents Commercial, and the overall representation is generally heat. Rolled steel plates and strips.
523) SPHD - the first S represents steel, the second P represents plate, the third H represents heat, the fourth D represents drawing, and the whole represents stamping. Hot rolled steel plates and strips.
534) SPHE - the first S represents steel, the second P represents plate, the third H represents heat, the fourth E represents deep drawing, and the whole represents hot rolling for deep drawing. Steel plates and steel strips.
545) SPCC - the first S represents Steel, the second P represents Plate, the third C represents Cold, the fourth C represents Commercial, and the overall expression is generally cold. Rolled carbon steel sheets and strips, equivalent to China's Q195-215A grade. When it is necessary to ensure the tensile test, add T at the end of the grade to indicate SPCCT.
556) SPCD - the first S represents Steel, the second P represents Plate, the third C represents Cold, the fourth D represents Drawing, and the whole represents stamping. Cold-rolled carbon steel sheets and strips, equivalent to China's 08AL (13237) high-quality carbon structural steel.
567) SPCE - the first S means steel, the second P means plate, the third C means cold, the fourth E means deep drawing, and the whole means cold rolling for deep drawing Carbon steel sheets and strips, equivalent to China's 08AL (5213) deep drawing steel. When non-timeliness needs to be ensured, add N to the end of the grade to indicate SPCEN.
57Other symbols:
581) Quenching and tempering codes of cold-rolled carbon steel sheets and steel strips: annealing state is A, standard quenching and tempering is S, 1/8 hardness is 8, 1/4 hardness is 4, 1/2 hardness is 2, and hardness is 1 .
592) Surface processing code: D for matte finish rolling and B for bright finish rolling. For example, SPCC-SD represents standard quenched and tempered, matte finish rolling, generally used cold-rolled carbon sheets. Another example is SPCCT-SB, which represents cold-rolled carbon sheets with standard tempering and bright processing, requiring guaranteed mechanical properties.
602.2.2 JIS mechanical structure steel grade expression method is:
61 The first part (S<Steel> steel) + the second part (carbon content: expressed as the middle value × 100) + the third part (letter code: the letter C represents carbon and K represents carburizing steel)
62 For example, the carbon content of carbon rolled plate S20C is 0.18-0.23%.
632.3 Representation method of some special Baosteel grades produced by Baosteel:
64 Baosteel 1550 cold rolled product brand naming method
65 (1) Nomenclature of cold rolled steel strip grades for stamping
661) General stamping steel: BLC
67B--Abbreviation of Baosteel; L--Low Carbon; C--Commercial
682) Aging-resistant low-yield steel: BLD
69B--Abbreviation of Baosteel; L--Low Carbon; D--Drawing
703) Non-aging extremely deep drawing steel: BUFD (BUSD)
71B--Abbreviation of Baosteel; U--Ultra; F--Formability;
72D--Drawing
734) Non-aging ultra-deep drawing steel: BSUFD
74B--Abbreviation of Baosteel; SU--Ultra+Super; F--Formability;
75D--Drawing
76 (2) Nomenclature of high-strength continuous cold-rolled steel strip for cold forming: B ××× × ×
77B--Abbreviation of Baosteel;
78×××--minimum yield point value;
79×--Generally represented by V, X, Y, Z
80V: high-strength low alloy, no regulation on the difference between yield point and tensile strength
81X: The difference between the minimum yield point in V and the minimum tensile strength is 70MPa
82Y: The difference between the minimum yield point in V and the minimum tensile strength is 100MPa
83Z: The difference between the minimum yield point in V and the minimum tensile strength is 140MPa
84×--Oxide/sulfide inclusion control (K: calm, fine grain; F: K+sulfide control; O: except K and F)
85 cases: B240ZK, B340VK
86 (3) Nomenclature of dent-resistant cold rolling steel strip grades: B ××× × ×
87B--Abbreviation of Baosteel
88×××--minimum yield point value
89×--Strengthening method (P: strengthening; H: baking hardening)
90×--represented by 1 or 2 (1: ultra-low carbon; 2: low carbon)
91 examples: B210P1: high-strength steel for deep drawing; B250P2: phosphorus-containing high-strength steel for general processing; B180H1: bake-hardened steel for deep drawing.
92 grades, properties and uses of commonly used steels
931. Some commonly used steel grades:
Types of 94 steel Specific product grades
95 carbon structural steel Q195 Q195F, Q195b, Q195
96Q215 Q215AF, Q215Ab, Q215A, Q215BF, Q215Bb, Q215B
97Q235 Q235AF, Q235Ab, Q235A, Q235BF, Q
235Bb, Q235B, Q235C, Q235D
98Q255 Q255A, Q255B
99Q275 Q275
100 Low alloy high strength structural steel General low alloy high strength structural steel Q295 Q295A, Q295B
101 Q345 Q345A, Q345B, Q345C, Q345D, Q345E
102 Q390 Q390A, Q390B, Q390C, Q390D, Q390E
103 Q420 Q420A, Q420B, Q420C, Q420D, Q420E
104 Q460 Q460C, Q460D, Q460E
105 Special-purpose low-alloy high-strength structural steel Special-purpose low-alloy high-strength structural steel generally uses the pinyin letter "Q" representing the yield point, the yield point value (unit: MPa), and is represented by the first letter of the pinyin of the product purpose at the end . For example: the steel grade for pressure vessels is expressed as "Q345R"; the steel grade for welding gas cylinders is expressed as "Q295HP"; the steel grade for boilers is expressed as "Q390g"; the steel grade for bridges is expressed as "Q420q", etc. The public account "Mechanical Engineering Literature", a gas station for engineers!
106 High-quality carbon structural steel 08F, 10F, 15F, 08, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 15Mn, 20Mn, 25Mn, 30Mn, 35Mn, 40Mn, 45Mn, 50Mn, 60Mn, 65Mn, 70Mn, 31 in total
107 Free-cutting structural steel Free-cutting structural steel is divided into sulfur-added free-cutting steel, sulfur-phosphorus-added free-cutting steel, lead-added free-cutting steel, calcium-added free-cutting steel, sulfur-added carbon-manganese free-cutting steel, etc. The grade is represented by prescribed symbols and Arabic numerals. That is, it starts with the first letter "Y" in the Chinese pinyin of "Yi", followed by two Arabic numerals to represent the carbon content in ten thousand. The specific brands are: Y12, Y12Pb, Y15, Y15Pb, Y20, Y30, Y35, Y40Mn, Y45Ca, a total of 9 brands
The grade of 108 alloy structural steel is expressed according to the carbon content of the steel and the type and quantity of alloying elements contained. This representation (preparation) method allows the rough chemical composition and quality grade of steel to be directly seen from the grade, which is relatively intuitive and concise. The specific grades are: 20Mn2, 30Mn2, 35Mn2, 40Mn2, 45Mn2, 50Mn2, 20MnV, 27MnSi, 35MnSi, 42MnSi, 20SiMn 2Mo, 25SiMn2MoV, 37SiMn2MoV, 40B, 45B, 50B, 40MnB, 45MnB, 20MnMoB, 15MnVB, 20MnVB, 40MnVB, 20MnTiB, 25MnTiBRE, 15Cr, 15CrA, 20Cr, 30Cr, 35Cr, 40Cr, 45Cr, 50Cr, 38CrSi, 12CrMo, 15CrMo, 20CrMo, 30CrMo, 30CrMoA, 35CrMo, 42CrMo, 12CrMoV, 35CrMo V, 12Cr1MoV, 25Cr2MoVA, 25Cr2Mo1VA , 38CrMoAl, 40CrV , 50CrVA, 15CrMn, 20CrMn, 40C rMn, 20CrMnSi, 25CrMnSi, 30CrMnSi, 30CrMnSiA, 35CrMnSiA, 20CrMnMo,
40CrMnMo, 20CrMnTi, 40CrMnTi, 20CrNi, 40CrNi, 45CrNi, 50CrNi, 12CrNi2, 12CrNi3, 20CrNi3, 30CrNi3, 37CrNi3, 12Cr2Ni4, 20Cr2Ni4, 20CrNiMo, 40CrNiMoA, 18CrNiMnMoA, 45CrNi MoVA, 18Cr2Ni4WA, 25Cr2Ni4WA total 77
109 Spring steel High quality carbon spring steel 65, 70, 85
110 Alloy spring steel 65Mn, 55Si2Mn, 55Si2MnB, 55SiMnVB, 60Si2Mn, 60Si2MnA, 60 Su2CrA, 60Si2CrVA, 55CrMnA, 60CrMnA, 60CrMnMoA, 50CrVA, 60CrMnBA, 30W4Cr2VA
111 Bearing Steel Chromium Bearing Steel Rolling bearing steel, referred to as bearing steel or ball steel, is a type of steel used to manufacture rings and rolling elements of various rolling bearings. The first letter "G" in Chinese Pinyin with the word "roll" added to the head of the grade indicates bearing steel. The specific grades are: GCr6, GCr9, GCr9SiMn, GCr15, GCr15SiMn, a total of 5 grades
112 Chromium-free bearing steel. The grade expression method is the same as that of chromium bearing steel. There are 6 grades in total: GSiMnV, GSiMnVXt, GSiMnMoV, GSiMnMoVXt, GMnM oV, and GMnMoVXt.
113 The specific grades of carburized bearing steel include: G20CrMo, G20CrNiMo, G20CrNi2Mo, G20Cr2Ni4, G10CrNi3Mo, G20Cr2Mn2Mo, etc.
European system European system The specific matching relationship between steel flange type, sealing surface type and nominal pressure PNg and industrial name through neck DN
