Q253 B What is the allowable stress at the design temperature?

Q235B is structural steel, which is cheaper. There should be corresponding standards for the selection of materials for the head, why this issue is not well understood.

Grade: Q235

Grade: bTensile Test|Yield point s mpa, |Steel thickness or diameter mm|≤16: 235

Tensile Test|Yield point s mpa, |Steel thickness or diameter mm|＞16～40: 225

Tensile Test|Yield point s mpa, |Steel thickness or diameter mm|＞40～60: 215

Tensile Test|Yield point s mpa, |Steel thickness or diameter mm|＞60～100: 205

Tensile Test|Yield point s mpa, |Steel thickness or diameter mm|＞100～150: 195

Tensile Test|Yield point s mpa, |Steel thickness or diameter mm|＞150: 185

Tensile Test|Tensile strength b mpa: 375 500

Tensile Test|Elongation δ5 (%) steel thickness or diameter mm|≤16: 26

Tensile Test|Elongation δ5 (%) steel thickness or diameter mm|＞16～40: 25

Tensile Test|Elongation δ5 (%) steel thickness or diameter mm|＞40～60: 24

Tensile Test|Elongation δ5 (%) steel thickness or diameter mm|＞60～100: 23

Tensile Test|Elongation δ5 (%) steel thickness or diameter mm|＞100～150: 22

Tensile Test|Elongation δ5 (%) steel thickness or diameter mm|＞150: 21

Impact Test|Temperature : 20

Impact Test|V-type (longitudinal) shock absorption work AK J, :27

Cold bending test, b=2a, 180°|Steel thickness or diameter mm|≤60|Diameter of the elbow core d mm: longitudinal a, horizontal.

Cold bending test, b=2a, 180°|Steel thickness or diameter mm|＞60～100|Diameter of the bent core d mm: longitudinal 2a, transverse.

Cold bending test, b=2a, 180°|Steel thickness or diameter mm|＞100～200|Diameter of the elbow core d mm: longitudinal and horizontal 3a

Hello dear, allowable stress = yield limit safety factor, the safety factor of q235 is, so the allowable stress is kn cm2. Allowable stress is the basic data in mechanical design and engineering structural design. In practical application, the allowable stress value is generally specified by the national engineering department according to the principle of safety and economy, according to the strength, load, environmental conditions, processing quality, calculation accuracy and importance of parts or components.

There is no strict absolute limit between plastic and brittle materials, so it is sometimes difficult to determine in advance whether the yield limit or the strength limit is used as a benchmark to determine the allowable stress. For example, the ratio of the yield limit to the strength limit (called the yield ratio) of mild steel is less than 1, so the allowable stress based on the yield limit is always less than the allowable stress based on the strength limit. With the adoption of high-strength steel, the yield ratio of the material continues to increase, and the opposite situation may occur.

Considering that there are two possibilities for determining the allowable stress, in the design of the parts or components working under static load at room temperature, the allowable stress in the two cases should be obtained at the same time, and the lesser value should be compared. In fatigue strength design, fatigue strength is generally calculated using the strength criterion expressed by the safety factor.

Allowable stress = yield limit safety factor, the safety sail permeability coefficient of Q235 is, the number of pants with the allowable potato sedan stress is kn cm2

Q235R is under allowable stress at 50.

Dear, hello, I am glad to answer for you that the allowable stress of Q235R at 50 is the allowable bending stress [ ]158MPa 235MPa Specifically, it should be adjusted according to the thickness or diameter of the material. This is the hand number of the hand of the check. It should be according to the national standard GB T 700.

Q235B steel compressive allowable stress, can only be calculated by allowable extrusion stress: [ suitable for plastic materials [ ] suitable for brittle materials [ ] for the allowable stress of the material. Q235 Mechanical Properties:

Modulus of elasticity (E GPA): 200 210 Poisson's ratio ( ) Tensile strength ( b MPa): 375-500 Elongation (δ5 %), 26 (A 16mm) 25 (A>16-40mm) 24 (A> 40-60mm) 23 (A>60-100mm) 22 (A>100-150mm) 21 (A>150mm).

Incorrect. That is the tensile strength, and the allowable stress is divided by a safety factor, which is used in different places.

Introduction: The maximum value of stress that a part or component is allowed to withstand in mechanical design or engineering structural design. In order to determine whether the working stress of a part or component is too high or too low after loading, it is necessary to determine a measurement standard in advance, which is the allowable stress.

When the working stress in the part or component does not exceed the allowable stress, the part or component is safe in operation, otherwise it is unsafe.

Q235 ordinary carbon structural steel is also known as A3 plate.

Ordinary carbon structural steel plate is a kind of steel material.

Q represents the yield limit of this material, and the subsequent 235 refers to the yield value of this material, which is about 235MPa. And with the increase of the thickness of the material, its yield value decreases (plate thickness diameter 16mm, yield strength of 235MPa; 16mm《Plate thickness diameter 40mm, yield strength of 225MPa; 40mm《Plate thickness diameter 60mm, yield strength of 215MPa; 60mm《Plate thickness diameter 100mm, yield strength of 205MPa; 100mm (plate thickness diameter 150mm, yield strength of 195MPa; 150mm (plate thickness diameter 200mm, yield strength 185MPa). Due to the moderate carbon content, the comprehensive performance is good, and the strength, plasticity and welding properties are well matched, and the most widely used.

It is composed of Q + number + quality grade symbol + deoxidation method symbol. Its steel number is crowned with "Q", which represents the yield point of the steel, and the following number indicates the yield point value, and the unit is MPA, for example, Q235 represents the yield stress (S) of carbon structural steel with 235 MPa.

If necessary, the steel number can be followed by a symbol indicating the quality grade and the method of deoxidation. The quality grade symbols are A, B, C, D. Deoxidation Method Symbol:

f denotes boiling steel; b for semi-sedative steel: z for sedative steel; tz stands for special sedative steel, and sedative steel can not be marked with symbols, that is, z and tz can not be marked.

Allowable stress = yield limit * (25 45)%.

It is recommended to refer to Table 3 of Q345R (Steel for Pressure Vessels) in GB713-2008-2008

Q345 is a steel material. It is a low-alloy steel, which is widely used in bridges, vehicles, ships, construction, pressure vessels, special equipment, etc. "q"It means yield strength, Q345 means that the yield strength of this steel is 345MPa.

q345a，q345b，q345c，q345d，q345e。This is the distinction of grades, which is represented, mainly because the temperature of the impact is different, and the Q345A grade does not do impact; Q345B, is 20 degrees normal temperature impact; Q345C grade, which is 0 degree impact; Q345D grade, is 20 degree punch; Q345E grade, is a 40-degree shock. The value of the impact varies depending on the impact temperature.

In the plate, it belongs to the low alloy series. Among the low-alloy materials, this material is the most common.

Mechanical properties of Q345 steel (%)

Grade: Wall thickness mm Elongation δ5 (% yield strength δs (mpa) Test temperature

Q345A 16 21 345 Not required.

q345b ≤16 21 345 20

q345c 16-35 22 ≥325 0

Mechanical properties of Q345D steel plate:

Yield Strength (MPa): 16mm: 345; 16-40mm:≥335;40-63mm:≥325;63-80mm:≥315;

80-100mm:≥305;100-150mm:≥285;150-200mm:≥275;200-250:≥275;

Tensile strength (mpa): 450-630.

Elongation: 21.

Impact test: -20: 34.

In fact, there are specific experimental data for this! Thank you for your acceptance!!

Which one of the Q345 is it? You can refer to the required stress table for Q345R in GB150.