What is the national standard for sheet thickness?

The allowable thickness deviation for stainless steel sheets is 0.2 mm.

Normal deviation of stainless steel plate: The thickness difference of the factory standard is generally ±0.02 mm, and the thickness difference of the national standard is generally ±0.5 mm. Stainless steel plate has a smooth surface, high plasticity, toughness and mechanical strength, and is resistant to corrosion from acid and alkaline gases, solutions and other media.

The national standard for solid wood flooring thickness is 18 mm. In addition to solid wood flooring, there are also standard thicknesses for engineered wood flooring and multi-layer engineered wood flooring. The former used to be mainly 8 mm thick, but now it is mainly 12 mm thick, while the latter is based on 15 mm thick.

The best solid wood flooring isn't necessarily the largest possible size; it's about finding the right fit for your needs. A common misconception is that larger planks have fewer seams and are more aesthetically pleasing. While larger sizes have their advantages, seams provide tension to the flooring, mitigating expansion and contraction from temperature changes and protecting it for longer. Therefore, the optimal size for solid wood flooring is under 0.6 meters!

3. National Standards for Steel Plate Thickness Tolerance

Steel plates are flat and rectangular, and can be directly rolled or cut from wide steel strips.

Steel plates are classified by thickness: thin steel plates are less than 4 mm (the thinnest being 0.2 mm), thick steel plates are 4 to 60 mm, and extra-thick steel plates are 60 to 115 mm.

Steel plates are divided into hot-rolled and cold-rolled.

Thin plates range in width from 500 to 1500 mm; thick plates range in width from 600 to 3000 mm. Thin plates are classified by steel type, including ordinary steel, high-quality steel, alloy steel, spring steel, stainless steel, tool steel, heat-resistant steel, bearing steel, silicon steel, and industrial pure iron thin plates; by application, including plates for oil drums, enamel plates, and bulletproof plates; and by surface coating, including galvanized thin plates, tin-plated thin plates, lead-plated thin plates, and plastic-coated steel plates.

The steel grades for thick steel plates are generally the same as those for thin steel plates. In terms of product range, apart from bridge steel plates, boiler steel plates, automobile manufacturing steel plates, pressure vessel steel plates, and multi-layer high-pressure vessel steel plates, which are purely thick plates, some steel plate varieties, such as automobile beam steel plates (2.5~10 mm thick), patterned steel plates (2.5~8 mm thick), stainless steel plates, and heat-resistant steel plates, overlap with thin plates.

The allowable deviation in steel plate thickness is generally within ±10%.

Standard precision requirements: If the steel plate width is <1250mm, the tolerance should be within ±0.22mm; if the steel plate width is >1250mm, the tolerance should be within ±0.23mm.

Higher precision requirements: If the width of the steel plate is within mm, the tolerance should be within ±0.11mm; if the width of the steel plate is within mm, the tolerance should be within ±0.12mm; if the width of the steel plate is >1250mm, the tolerance should be within ±0.14mm.

Both of the above precision requirements comply with the national standard: GB/T Stainless Steel Cold Rolled Steel Sheets and Strips

1. The allowable deviations in the dimensions and shape of angle steel shall comply with the GB/T standard for hot-rolled steel sections.

2. The GB/T standard for hot-rolled steel sections clearly states:

1) Dimensions, shape, weight, permissible deviations, technical requirements, and test methods of hot-rolled equal angle steel, hot-rolled unequal angle steel, hot-rolled L-shaped steel, etc.

2) The mechanical properties, steel grade and chemical composition of the structural steel shall comply with the relevant provisions of GB/T700 carbon steel and GB/T1591 low alloy high strength structural steel.

3) Allowable deviations in the dimensions and shape of angle steel

The thickness tolerance of steel plates according to national standards can be found in the national standard GB "Dimensions, Shapes, Weights and Permissible Deviations of Hot-Rolled Steel Plates and Strips".

Currently, the national standard for aluminum plate thickness is GB/T "Aluminum and Aluminum Alloy Plates and Strips". This standard specifies the following commonly used aluminum plate thicknesses:

1. Ordinary aluminum sheet in hot-rolled condition: thickness of 4~200mm.

2. Ordinary aluminum sheet in cold-rolled condition: thickness 0.20~6.35mm.

3. Ordinary aluminum plates in the casting state: thickness is 6~200mm.

Furthermore, in practical applications, there are some special requirements and needs that need to be formulated and adjusted according to specific circumstances. Therefore, when selecting and using aluminum plates, it is recommended to refer to relevant industry standards or consult professionals to ensure that they meet actual needs.

Ordinary thin steel sheet thickness (mm): 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.7 0.75 0.8 0.9 1.0 1.1 1.2 1.25 1.4 1.5 1.6 1.8 2.0 2.2 2.5 2.8 3.0 3.2 3.5 3.8 4.0 Pickled thin steel sheet and galvanized thin steel sheet thickness (mm): Nominal dimensional tolerance 0......50±0.05 0.55±0.06 0.60 0.65 0.70±0.07 0.75 0.80±0.08 0.90 1.00±0.09 1.10 1.20±0.11 1.30 1.40±0.12 1.50 1.60±0.14 1.80 2.00±0.15 Thick steel plate thickness (mm): 4.555.0

Q235 = 0.6 - 0.8, Q345 = 0.25.

When selecting the negative tolerance for the thickness of steel plates or pipes, it should be selected according to the provisions of the corresponding steel standards. When the negative tolerance for the thickness of the steel is no greater than 0.25mm and does not exceed 6% of the nominal thickness, the negative tolerance for the thickness of the steel can be ignored.

For pressure vessels

Carbon structural steel

For hot-rolled steel plates Q235-B and Q235-C (GB/T912, GB/T3274) and stainless steel hot-rolled steel plates (GB/T4237), the negative tolerance of thickness shall be in accordance with the provisions of GB/T for the dimensions, shape, weight and permissible deviations of hot-rolled steel plates and strips.

When stainless steel cold-rolled steel sheet (GB/T3280, thickness not greater than 4mm) is selected, its thickness negative deviation shall be in accordance with the provisions of GB/T cold-rolled steel sheet and steel strip regarding size, shape, weight and permissible deviation. For composite steel sheet and seamless steel pipe, the thickness negative deviation shall be in accordance with the provisions of the corresponding steel standard.

Extended Information:

Precautions for steel:

1. The principle of stacking is to stack materials according to variety and specifications, ensuring that the stacking is stable and safe. Different varieties of materials should be stacked separately to prevent confusion and cross-corrosion.

2. For steel sections stored in the open air , there must be wooden pads or stone blocks underneath, and the stack surface should be slightly tilted to facilitate drainage. Also, ensure that the materials are placed flat to prevent bending and deformation.

3. The stacking height shall not exceed 1.2m for manual operations and 1.5m for mechanical operations, and the stack width shall not exceed 2.5m.

4. Raise the base of the stack. If the warehouse has a sunny cement floor, raise it by 0.1m. If it is a dirt floor, raise it by 0.2-0.5m. If it is an open-air area, raise it by 0.3-0.5m for cement floors and 0.5-0.7m for sandy or muddy floors.

5. Angle steel and channel steel should be laid face down when stored in the open air, i.e., with the opening facing down. I-beams should be placed upright. The I-shaped groove of the steel should not face up to prevent water accumulation and rust.

Reference source:

Baidu Baike - Board Material

Reference source:

Baidu Baike - Steel

Reference source:

Baidu Baibanjiaoke-Q235

Reference source:

Baidu Baike (Baidu Encyclopedia) - Q345

Reference source:

Baidu Baike - Thickness Tolerance

Reference source:

Baidu Baike - Stainless Steel Cold Rolled Steel Sheet

Q235 = 0.6~0.8

Q345=0.25

The "Pressure Vessel Design Engineer Training Course 2005" explains negative thickness deviation as follows:

1. When selecting the negative tolerance for the thickness of steel plates or steel pipes, it should be selected in accordance with the provisions of the corresponding steel standards.

2. When the negative deviation of the steel thickness is no greater than 0.25 mm and does not exceed 6% of the nominal thickness, the negative deviation of the steel thickness can be ignored.

3. The negative thickness deviation of steel plates used in pressure vessels in my country is 0.25 mm.

4. For hot-rolled carbon structural steel plates Q235-B and Q235-C (GB/T912, GB/T3274) and stainless steel hot-rolled plates (GB/T4237) for pressure vessels, the negative tolerance of their thickness shall be in accordance with the provisions of GB/T "Dimensions, Shapes, Weights and Permissible Deviations of Hot-rolled Steel Plates and Strips".

When stainless steel cold-rolled steel sheet (GB/T3280, thickness not greater than 4mm) is selected, its thickness negative deviation shall be in accordance with the provisions of GB/T "Dimensions, shape, weight and permissible deviations of cold-rolled steel sheet and strip".

The negative thickness tolerances for composite steel plates and seamless steel pipes shall be specified in the corresponding steel standards.