Stainless Steel Thickness Chart (Standard vs. Real Thickness)

Have you ever wondered about the difference between the standard and actual thickness of stainless steel? In this blog post, we’ll dive into this intriguing topic, exploring the key factors that influence these measurements. Drawing from industry standards and expert insights, we’ll unravel the mysteries behind stainless steel thickness and equip you with valuable knowledge for your next project.

Table Of Contents

1. Understanding the Discrepancy Between Nominal and Actual Thicknesses in Stainless Steel

In stainless steel manufacturing and fabrication, it’s crucial to distinguish between nominal (standard) thickness and actual thickness:

Nominal Thickness:
This refers to the designated or specified thickness of stainless steel sheets or plates, typically expressed in whole numbers or common fractions (e.g., 1mm, 2mm, 3mm, 4mm). These values are used for general classification and ordering purposes.

Actual Thickness:
This is the precise, measured thickness of the stainless steel material, usually determined using high-precision measuring tools. Actual thickness is generally reported to two decimal places (e.g., 0.85mm, 1.91mm, 2.75mm, 3.80mm) for enhanced accuracy in engineering and fabrication processes.

The discrepancy between nominal and actual thickness is attributed to manufacturing tolerances, which are necessary due to the complexities of the steel production process. These tolerances are typically defined by international standards such as ASTM A480 or EN 10029, which specify acceptable thickness variations for different grades and dimensions of stainless steel.

Understanding this distinction is vital for:

  1. Precise engineering calculations and design
  2. Ensuring proper material selection for specific applications
  3. Quality control and compliance with industry standards
  4. Accurate cost estimation and material procurement

Manufacturers and fabricators must always consider actual thickness when planning precise machining operations, calculating material strength, or designing tight-tolerance assemblies.

2. What is the difference between the standard and actual thicknesses of stainless steel plates?

The difference between the standard and actual thicknesses of stainless steel plates is governed by specific material standards and manufacturing tolerances. This variance is crucial for precision engineering and quality control in metal fabrication processes.

Stainless steel plate thickness standards can be categorized based on various national and international specifications:

  1. Pressure-bearing standard: GB/T24511-2017
  2. Hot-rolled national standard: GB/T4237-2015
  3. Cold-rolled national standard: GB/T3280-2015
  4. Cold-rolled American standard: ASTM A240/A240M-15a

The first three standards mentioned are Chinese national standards that define the thickness tolerances for stainless steel plates. These tolerances account for the inherent variations in the manufacturing process, including factors such as rolling precision, material properties, and cooling rates.

To illustrate the practical differences between standard and actual thicknesses, consider the following comparison for stainless steel plates with a width of 1.2m:

Table ① and Table ②: Comparison between standard thickness and actual thickness of stainless steel plates (width: 1.2m)

Standard thickness and actual thickness comparison table of stainless steel plate ①

Standard thicknessReal thickness
(when the width of the steel plate is 1.2m)
(unit: mm)
GeneralComply with pressure-bearing standard
GB/T24511-2017
Conform to the national standard of hot rolling
GB/T4237-2015
Conform to the national standard of cold rolling
GB/T3280-2015
Conform to American Standard for Cold Rolling
ASTM A240/A240M-15a
0.50.3~0.50.45~0.550.46~0.54
0.80.6~0.80.71~0.890.75~0.85
10.8~10.9~1.10.94~1.06
1.21~1.20.9~1.11.12~1.28
1.51.2~1.51.38~1.621.42~1.58
21.6~21.78~2.221.83~2.1719~2.1
2.52.2~2.51.78~2.222.28~2.722.4~2.6
32.6~32.75~3.252.75~3.252.78~3.222.87~3.13

Comparison Table of Standard Thickness and Actual Thickness of Stainless Steel Plate ②

Standard thicknessReal thickness
(when the width of the steel plate is 1.2m)
(unit: mm)
GeneralComply with pressure-bearing standard
GB/T24511-2017
Conform to the national standard of hot rolling
GB/T4237-2015
Conform to the national standard of cold rolling
GB/T3280-2015
Conform to American Standard for Cold Rolling
ASTM A240/A240M-15a
43.5~43.72~4.283.72~4.283.75~4.253.83~4.17
54.5~54.7~5.314.69~5.314.65~5.354.83~5.17
65.5~65.7~6.335.67~6.335.6~6.45.8~6.2
87.5~87.7~8.387.62~8.387.5~8.57.77~8.23
109.5~109.710.429.58~10.42
1211.5~1211.7~12.4511.55~12.45
1413.5~1413.7~14.4513.55~14.45
1615.5~1615.7~16.515.55~16.45

Table ③ and Table ④:

When the width of steel plate is 1.5m, the standard thickness and actual thickness of stainless steel plate are compared as follows:

Standard thickness and actual thickness comparison table of stainless steel plate ③

Standard thicknessReal thickness
(when the width of the steel plate is 1.5m)
(unit: mm)
GeneralComply with pressure-bearing standard
GB/T24511-2017
Conform to the national standard of hot rolling
GB/T4237-2015
Conform to the national standard of cold rolling
GB/T3280-2015
Conform to American standard
STMA240/A240M-15a of cold rolling
0.50.3~0.50.42~0.58
0.80.6~0.80.7~0.9
10.8~10.88~1.120.92~1.08
1.21~1.21.08~1.321.12~1.28
1.51.2~1.51.35~1.651.4~1.6
21.6~21.8~2.21.89~2.11
2.52.2~2.52.25~2.752.37~2.63
32.6~32.72~3.282.72~3.282.75~3.252.85~3.15

Comparison Table of Standard Thickness and Actual Thickness of Stainless Steel Plate ④

Standard thicknessReal thickness
(when the width of the steel plate is 1.5m)
(unit: mm)
GeneralComply with pressure-bearing standard GB/T24511-2017Conform to the national standard of hot rolling GB/T4237-2015Conform to the national standard of cold rolling GB/T3280-2015Conform to American Standard for Cold Rolling ASTM A240/A240M-15a
43.5~43.7~4.313.69~4.313.6~4.43.83~4.17
54.5~54.7~5.334.67~5.334.55~5.454.81~5.19
65.5~65.7~6.365.64~6.365.556.455.77~6.23
87.5~87.7~8.397.61~8.397.5~8.57.75~8.25
109.5~109.7~10.439.57~10.43
1211.5~1211.7~12.4711.53~12.47
1413.5~1413.7~14.4713.53~14.47
1615.5~1615.7~16.5315.53~16.47

The standard for the actual thickness of stainless steel 304 is the same as the previous example.

The actual thickness of stainless steel 304 can be determined based on the relevant width and standard of the stainless steel plate.

3. Impact of Standard and Actual Thickness of Stainless Steel

In stainless steel manufacturing and procurement, it’s crucial to understand the distinction between standard (theoretical) thickness and actual thickness. This difference has significant implications for material properties, cost calculations, and engineering applications.

Standard thickness, also referred to as nominal or theoretical thickness, represents the designated size category for stainless steel plates. However, due to manufacturing tolerances and rolling processes, the actual thickness typically falls slightly below this nominal value. For example, a stainless steel plate marketed as 3mm thick may have an actual thickness ranging from 2.75mm to 2.8mm.

This variance is industry-accepted and complies with international standards such as ASTM A480/A480M, which specifies thickness tolerances for stainless steel sheets and plates. Understanding these tolerances is critical for engineers and buyers to ensure that the material meets design specifications and performance requirements.

When purchasing stainless steel plates, awareness of this thickness differential is essential for several reasons:

1. Material Properties: Slight variations in thickness can affect mechanical properties, weight-bearing capacity, and corrosion resistance.

2. Cost Calculations: Pricing mechanisms vary based on how thickness is considered:

  • Weight-based pricing: When cost is calculated by actual weight, the price per unit is primarily influenced by market conditions and material grade. This method ensures you pay for the exact amount of material received.
  • Theoretical weight pricing: If pricing is based on standard thickness, the unit cost incorporates the thickness differential, market factors, and material quality. This approach may result in a slightly higher cost per actual weight received.

3. Engineering Tolerances: Design engineers must account for thickness variations in their calculations, especially for precision applications or when tight tolerances are required.

4. Quality Control: Understanding the expected thickness range aids in quality assurance processes and helps prevent disputes with suppliers.

To optimize material selection and cost-effectiveness, consider the following best practices:

  • Clearly specify required thickness tolerances in purchase orders.
  • For critical applications, consider ordering slightly thicker material to ensure minimum thickness requirements are met after processing.
  • Implement incoming material inspection procedures to verify actual thicknesses.
  • Work closely with suppliers to understand their manufacturing capabilities and typical thickness variations.

By comprehending the nuances of standard versus actual thickness in stainless steel plates, professionals can make more informed decisions, ensure project success, and optimize material utilization in various industrial applications.

See also: Calculation formula for steel plate weight

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Shane
Author

Shane

Founder of MachineMFG

As the founder of MachineMFG, I have dedicated over a decade of my career to the metalworking industry. My extensive experience has allowed me to become an expert in the fields of sheet metal fabrication, machining, mechanical engineering, and machine tools for metals. I am constantly thinking, reading, and writing about these subjects, constantly striving to stay at the forefront of my field. Let my knowledge and expertise be an asset to your business.

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