Q275 steel JO is different from JR

European Standard S275JR

Chemical composition. Mass fraction) (%c: mn: si: s: grade) p: deoxidation method: z[1].

Mechanical properties. Tensile strength (b mpa): 490-630 elongation (δ5%):

20(A>16mm), 19(A>16-40mm), 18(A40-60mm), 17(A>60-100mm) 16(A>100-150mm), 15(A>150mm)[2] where A is the thickness or diameter of the steel. Elongation (δ5 %): 26 (A 16mm) 25 (A>16-40mm) 24 (A>40-60mm) 23 (A>60-100mm) 22 (A>100-150mm) 21 (A>150mm) where a is the thickness or diameter of the steel.

Executive standard: The external standard is: GB T709-2006 "Size, shape, weight and allowable deviation of hot-rolled steel plate and steel strip", and the internal standard is:

GB T3274-2007 "Carbon Structural Steel and Low Alloy Structural Steel Hot Rolled Thick Steel Plate and Steel Strip".

Cold-formed performance. 180° cold bending test d=3a (b=2a: 60mm), d=4a (b=2a:

60 100mm), d=: >100 200mm) where d is the bending diameter, b is the width of the specimen, and a is the thickness or diameter of the steel.

Key features: It has high strength, good plasticity and cutting performance, and certain welding performance. Small parts can be quenched and strengthened.

Application examples: It is used in the manufacture of parts that require high strength, such as gears, shafts, sprockets, keys, bolts, nuts, sections for agricultural machinery, conveyor chains and chain links. Mainly used in construction. The production of more important mechanical components in bridge engineering.

S275J0 low alloy.

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1. The yield limit is different: the yield limit of Q235 is 235MPa; The Q275 has a yield limit of 275MPa. They are all ordinary carbon structural steel, Q represents the yield limit of this material, and the following number refers to the yield value of this material.

2. Carbon content and tensile strength are not the same: Q235 carbon content, tensile strength 375-500; Q275 carbon content, tensile strength of the carbon content is generally greater than Q235 carbon content, tensile strength is also larger.

3. Applicability is different: Q235 is used in building and engineering structures, such as making steel bars or building factory trusses, high-voltage transmission towers, vehicles, boilers, containers, ships, etc. Q275 is used to manufacture parts that require high strength, such as gears, shafts, sprockets, nuts, agricultural steel sections, conveyor chains, and chain links.

Q235 and Q275 are ordinary carbon structural steel plates, with different strengths, 3mm-400mm

The yield strength limits are different, one is and one is. If memory serves, :)

The biggest difference between these two steels is the impact requirements, S275JR does room temperature impact, and S275JO does zero degree impact.

S275 is equivalent to Q275, and S275JR has to have an impact of 0, indicating that S275JR is more resistant to low temperatures than S275. The strength of Q345B is higher than that of S275 and can be replaced.

The impact temperature of the S235JR is 20 degrees Celsius, and the impact temperature of the S235J0 is 0 degrees. It is equivalent to the difference between GB Q235B and Q235C.

S235JR is a non-alloy structural steel of the European standard, which is equivalent to the Q235B of the national standard, that is, carbon structural steel with a lower carbon content, which is used for welding, bolting, and riveting structures

Unalloyed steel is to say: not alloy steel. S235JR is a new grade of special steel for containers or pipes, which has been annealed and is relatively soft and can be rolled into pipes.

Q235 is a general steel, its lowest yield point is 235MPa, if it is not used for drawing tubes, the strength of the two steels is the same, can be universal.

This standard is compared with the reference standard and the national standard.

Table Q BQB 610-2004 DIN17100 80 EN10025:1990 PREN10025-2:1998 GB T 3274 88

s185 st33 fe310-0 s185 q195，q215a，q215b

s235jr st37-2 fe360b s235jr q235b

s275jr st44-2 fe430b s275jr q255b

s355jr - fe510b s355jr q345b，q390b

The chemical composition of the finished products of S235JR, S275JR and S355JR shall comply with the provisions of Table 3, and the supplier may not be analyzed if it can guarantee it.

Grade: Nominal thickness, mm, chemical composition (melting analysis) %

c si mn p s other.

s235jr 5～40 ≤ n≤

s235jr >40～150 ≤ n≤

s275jr 5～40 ≤ n≤

s275jr >40～150 ≤ n≤

s355jr 5～150 ≤ n≤

The carbon equivalent grades S235JR, S275JR and S355JR should be in accordance with Table 4.

Table 4 Grades of carbon equivalent, CEQA, %.

Thickness, MMS235JR 40 40 150

s235jr

s275jr

s355jr

Carbon equivalent is calculated based on the melting analysis.

According to the above data, the two types of steel can be substituted if they are used for general structural parts. Except in exceptional circumstances. Certainly not stainless steel.

Steel for pressure vessels refers to the steel used in the manufacture of pressure vessel shells, heads and other components, mainly high-quality carbon steel, high-quality low-alloy steel and alloy steel. This type of steel has strict requirements for chemical composition and quality control, to ensure minimum strength and sufficient toughness to be suitable for welding, and if necessary, must meet special performance requirements for high and low temperatures. The commonly used steel for pressure vessels includes carbon steel and low-alloy steel plate for pressure vessels specified in GB6654, low-alloy steel plates for multi-layer pressure vessels specified in GB6655, steel plates for welded gas cylinders specified in GB6653, low-alloy steel and alloy steel thick steel plates for low-temperature pressure vessels specified in GB3531.

In addition, some special equipment (such as chemical, petroleum, aerospace, aviation, ships, etc.) requires high-pressure vessels, and special quality high-strength steel and ultra-high-strength steel are also used.

Steel S355JR and S355J2 have different requirements for toughness impact energy, and other mechanical properties and various requirements are the same.

S355JR toughness impact power requirements: 20, impact energy 27JS355J2 toughness impact power requirements: -20, impact energy 27J As the temperature decreases, the impact energy of the same piece of steel will gradually decrease, so S355J2 is a little more expensive.

The corresponding national standard of the European standard S235JO is Q235C or Q255B, and the corresponding national standard of the European standard S235JR is Q235B

The European standard S355JR corresponds to the national standard Q345B

For details, see GBT6725-2002 cold-formed steel.

S355 Low Alloy Structural Steel S355 Chemical Composition: S355 Composition C ; mn≤；si≤；p、s≤；n, there is no corresponding brand in China. S355 is EN10025-3:2004

1. S355J0 details:

S355J0 is a kind of carbon structural steel plate produced by the European standard, which is similar to the performance, composition and use of Q345B steel plate under the national standard. However, some details of these two types of steel plates are still different and cannot be completely replaced.

2. Carbon structural steel.

Carbon steel, which is used in buildings, bridges, ships, vehicles and other structures, must have a certain strength, and require impact performance and welding performance if necessary.

3. The implementation standard of S355J0: This brand implements the European standard EN10025-2:2004 standard.

4. The delivery status of S355J0: The steel plate is mostly delivered in the delivery state of hot rolling, controlled rolling, normalizing, etc. PS: If the customer has other performance requirements, the delivery status requirements should be indicated in the contract.

5. Packaging, marking and quality certificate of S355J0: The packaging, marking and quality certificate of steel plate shall comply with the provisions of GB T 247.

6. Chemical composition of S355J0 (element composition: wt%):

Carbon C: Silicon Si:

Manganese Mn: Phosphorus P:

Sulfur s: copper cu:

PS: The specific chemical composition should be indicated in the steel mill material book.

7. Mechanical properties of S355J0: yield strength:

Tensile strength: 450-680

PS: The specific mechanical properties should be indicated in the material book of the steel mill.