What is Q235-AF steel in forging production?
- Feb 28, 2018 -

China here is based on the use of steel classification as the basis for the classification of methods:


1 Carbon Structural Steel

Method: q+ number + (Quality level symbol) + (Deoxidation method symbol) + (Special purpose symbol)

The ① steel number is labeled "Q", which represents the yield point of the steel;

The number following the ② "Q" indicates the value of the yield point, which is MPA. For example, Q235 indicates that the yield point (σs) is a carbon structural steelof 235 MPa;

③ when necessary, the symbol indicating the quality grade and Deoxidation method can be marked after the steel number. The quality grade symbols are a, B, C, D respectively.

Deoxidation method symbol: F means boiling steel; b means half calm steel: Z means calm steel; TZ Express Special sedative steel, calm steel is not a sign, that is, Z and TZ can not be marked. For example, Q235-AF represents a-level boiling steel.

Special-Purpose carbon steel: for example, Bridge Steel, marine steel, etc., basically using carbon structural steel representation, but at the end of the steel to attach the letter of use.


2 high quality carbon structural steel

Presentation method: Number + (Yuansu) + (Deoxidation method symbol) + (Special purpose symbol)

The two-digit number at the beginning of the ① steel indicates the carbon content of the steel, in the extreme of the average carbon content, such as steel with an average carbon content of 0.45%, and the steel number "45", which is not a sequential number, so it cannot be read as 45th steel.

For high quality carbon structural steels with high manganese content, the manganese elements should be ②, such as 50Mn.

③ boiling steel, semi-calming steel and special-purpose high-quality carbon Structural steels should be marked at the end of the steel number, such as a half-calm steel with an average carbon content of 0.1%, with a steel number of 10b.


3 Carbon tool Steel

notation: Letter t+ number + (Yuansu) + (Quality level symbol)

The ① steel number is labeled "T" to avoid mixing with other steel types.

The number in the ② steel indicates the carbon content, which is expressed in a thousand-point average carbon content. For example, "T8" means an average carbon content of 0.8%.

③ manganese content is higher, at the end of the steel number marked "MN", such as "t8mn".

④ High quality carbon tool steel, phosphorus, sulfur content, lower than the general quality carbon tool steel, in the final add letter "A", to show the difference, such as "T8mna."


4) Easy Cutting steel

notation: Letter y+ number + (Yuansu)

① steel is labeled "Y" to distinguish it from high quality carbon structural steels.

The ② of the letter "Y" indicates the carbon content, which is expressed in a very extreme amount of carbon, such as a 0.3%-cut steel with an average carbon content of "Y30".

③ manganese content is higher, also after the steel number marked "MN", for example "y40mn".


5 Alloy Structural Steel

Presentation method: (Special purpose symbol) + numeral + main alloy Yuansu and numeral + trace alloy Yuansu + (quality grade symbol) + (Special purpose symbol)

The two-digit number at the beginning of the ① steel represents the carbon content of the steel, expressed in a very extreme amount of carbon, such as 40Cr.

The main alloying elements in ② steel, except for individual micro-alloying elements, are generally expressed in a few percent. When the average alloy content <1.5%, the steel number generally only mark the element symbol, but does not indicate the content, but in the special situation is apt to confuse, after Yuansu also can mark the numeral "1", for example steel number "12CrMoV" and "12cr1mov", the former chromium content is 0.4-0.6%, The latter is 0.9-1.2% and the remainder is the same. When the alloying element average content ≥1.5%, ≥2.5%, ≥3.5% ... , the content should be indicated after the Yuansu, which can be expressed as 2, 3, 4 ... Wait。 such as 18cr2ni4wa.

③ Steel vanadium V, Ti ti, Al al, Boron B, re and other alloy elements, are micro-alloying elements, although the content is very low, still should be awarded in the steel number. For example 20MnVB Steel: Vanadium is 0.07-0.12% and boron is 0.001-0.005%.

④ high-quality high-quality Steel should be in the final add "A", to distinguish from the general high-quality steels.

⑤ Special-purpose alloy structural steel, with a steel number (or suffix) representing the use of this steel. For example, the 30CrMnSi steel for riveting snail, the steel number is indicated as Ml30crmnsi


6 Low alloy high strength steel

Presentation method: (Special purpose symbol) + numeral + main alloy Yuansu and numeral + trace alloy Yuansu + (quality grade symbol) + (Special purpose symbol)

The method of ① steel number is basically the same as that of alloy structural steel.

② for professional low alloy high-strength steels, shall be marked at the end of the steel number. For example, 16Mn steel, the special steel for the bridge for the "16Mnq", the special steel for the automotive beam for "16MnL", pressure vessels dedicated steel for "16MnR."


7) Spring Steel

Spring steel According to chemical composition can be divided into carbon spring steel and alloy spring steel Two, its steel number method, the former is basically the same as high-quality carbon structural steel, the latter is basically the same as the alloy structural steel.


8 Rolling Bearing Steel

Presentation method:

High carbon chromium bearing steel: letter G+CR Yuansu and digital

carburized Bearing Steel: letter g+ number + main alloy Yuansu and numeral + trace alloy Yuansu + (quality grade symbol)

The ① steel is labeled "G", which indicates the steel type of rolling bearing.

The carbon content of ② high carbon chromium bearing steel is not marked, and the content of chromium is expressed in thousands of points, such as GCR15. The steel number method of carburized bearing steel is basically the same as that of alloy structural steel.


9 Alloy tool steel and high speed tool steel

When the average carbon content of ① alloy tool steel is ≥1.0%, the carbon content is not marked; When the average carbon content is <1.0%, it is expressed in thousands of points. such as Cr12, CRWMN, 9SiCr, 3Cr2W8V.

The determination of alloying element content in ② steel is basically the same as that of alloy structural steel. However, the chromium content of the alloy tool steel with low chromium content is expressed in thousands of points, and it is added "0" to the number of the content, in order to distinguish it from the general element content by a percentage of the method. such as Cr06.

The steel number of ③ high speed tool steel generally does not mark the carbon content, but only the percentage of the average content of various alloying elements. For example, the steel number of tungsten high-speed steel is expressed as "w18cr4v". The steel number is labeled "C", which means that the carbon content is higher than the general steel number of "C" without crown.


10 stainless steel and heat-resisting steels

The carbon content in the ① steel number is expressed in thousand-percent. For example, "2Cr13" Steel has an average carbon content of 0.2%, if the steel containing carbon content ≤0.03% or ≤0.08%, before the steel number is labeled "00" and "0", such as 00cr17ni14mo2, 0cr18 Ni9 and so on.

The main alloying elements in steel are expressed as a percentage of ②, while titanium, niobium, zirconium, nitrogen ... And so on the alloy structural steel to the micro-alloying elements of the presentation method.

11) Welding Rod Steel

Its steel number is preceded by the letter "H" to distinguish it from other steel types. For example, stainless steel wire for "h2cr13", can be distinguished from the stainless steel "2Cr13".


12 silicon steel for electrical purposes

The ① steel number consists of letters and numbers. Steel Head Letter Dr Indicates hot-rolled silicon steel for electrical purposes, DW means cold-rolled, non oriented silicon steel for electrical purposes, and DQ is a cold rolled oriented silicon steel for electrical purposes.

The number after the ② letter represents 100 times times the value of the Iron loss (w/kg).

③ the end of the steel number with the letter "G", said the test at a high frequency, without "G", the frequency of 50-week wave test.

For example, the steel DW470 indicates that the maximum unit weight iron loss of a cold rolled non oriented silicon steel product at 50 khz frequency is 4.7w/kg.


13 Pure Iron for electrician

① its brand by the letter "DT" and the number of components, "DT" means the electrician with pure iron, the number of different grades of the order number, such as DT3.

② the letters appended to the numbers indicate electromagnetic properties: a--, e--, c--super, such as dt8a.