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1. What material data do I need for structural design?

Several material properties are essential for structural design. The yield strength, tensile strength and elastic modulus (Young's modulus) are often the critical parameters for static loads that must be known to ensure the structural integrity and safety of the design. Other properties such as density, ductility, toughness, fatigue strength and hardness may also be important depending on the specific application. Designers should always refer to the material data sheets available from material suppliers for accurate and complete information on the materials they plan to use. It is crucial to select the right material for the intended application and to ensure that all relevant material properties are within the required limits.

2. What material data do I need for material processing (such as bending, welding, cutting, etc.)?

The material properties required for material processing vary depending on the specific manufacturing process. For instance, ductility, yield strength and elastic modulus are critical for bending operations, while melting point, thermal conductivity and expansion coefficient are important for welding. In contrast, hardness and toughness are significant for cutting.

The material thickness and form tolerances, such as flatness and surface finish, are also crucial considerations for various processing methods.To ensure successful material processing, it's crucial to understand the material properties that affect the specific manufacturing process. Material data sheets and expert advice from material suppliers can help you to identify the relevant properties for each process. It's also important to select materials that are suitable for the intended application and that can be processed using the available equipment and expertise.

3. Which material data do I need to perform an FEA simulation?

To perform an FEA (finite element analysis) simulation, you need to have accurate material data to accurately model the behavior of the material. The yield strength and Young's modulus are generally needed to define the material's elastic behavior. Additionally, many material models require a stress-strain curve as input to capture the material's plastic behavior.

In addition to the yield strength and Young's modulus, FEA simulations may require other material data depending on the simulation's complexity and accuracy requirements. For example, some simulations may require a more detailed material model, such as a nonlinear or viscoelastic material model, which would require additional material data such as Poisson's ratio, thermal expansion coefficient and creep data. Since different FEA software packages may also have different material models available, it's important to choose the appropriate material model based on the simulation requirements and the available material data. You can often obtain material data from material suppliers, testing labs or from publicly available databases.

Read more about Material data for SolidWorks® and Material library for Autodesk® Inventor®.

4. What material data is included in material standards?

Material standards are developed and published by standardization organizations, such as ISO, ASTM International or other regional bodies, and are used as a reference for material selection and quality control. In general, these standards specify the allowable limits of different data, such as chemical composition and mechanical properties, and provide guidance on material testing and inspection requirements. These standards are not a substitute for data sheets or material certificates. Additionally, material suppliers often include the available formats of their material qualities, such as thickness, width and length of steel sheets, as well as tolerances in their data. 

Material standards play an essential role in ensuring the quality and consistency of materials used in various applications. The material data included in these standards varies depending on the specific material and its intended use. Typically, material standards define the minimum and maximum allowable limits for chemical composition, mechanical properties such as tensile strength and yield strength, and other characteristics such as hardness, toughness, and ductility. It is important to select the appropriate material standard based on the intended application and to verify that the material properties meet the requirements of the standard. In addition, material standards may provide guidance on material testing and inspection requirements, including sample preparation, test methods and acceptance criteria. Material standards can often be obtained from standardization organizations, material suppliers or industry associations.

5. Where can I find material data for SSAB steel grades?

You can find material data for SSAB steel grades on the SSAB website (www.ssab.com) under the "Products" section. On the product pages, you can find information on the chemical composition, mechanical properties, available formats and other relevant data for each steel grade. In addition to product information, SSAB also provides various downloads including brochures, technical data sheets and material certificates, which contain detailed information about the properties and characteristics of their products. These downloads can be accessed from the product pages or from the SSAB Download center. SSAB also offers technical support and can assist with any questions or concerns regarding their products.

6. What is the difference between guaranteed, typical and nominal values?

Guaranteed values are given for properties that are measured and controlled to be within defined limits. Products with properties outside of these limits will not be delivered. Since all properties have spread and variation, typical values indicate what value could most commonly be expected. Nominal values are convenient when describing a product in general, but cannot be used for engineering and design purposes. 

The difference between guaranteed, typical, and nominal values lies in the level of certainty associated with each value. It's important to understand the difference between these values and to select the appropriate value based on the level of certainty required for a particular application.

  • Guaranteed values are the properties of a product that are measured and controlled to be within defined limits and are typically used as the basis for product specifications. These values are critical because products that do not meet these specifications will not be delivered to customers.
  • Typical values indicate what value could most commonly be expected based on a statistical analysis of a large number of measurements. While typical values are not guaranteed, they can be used as a guide to the expected properties of a product and the average process behavior of the material.
  • Nominal values are values that are specified as part of a product description, but do not necessarily reflect the actual properties of the product. Nominal values are often used as a convenient way to describe a product, but should not be relied upon for precise engineering calculations or material selection.

In summary, guaranteed values provide the highest level of certainty, typical values provide a guide to the expected properties, and nominal values provide a general description of the product. When selecting a material, it's important to consider the level of precision required for the application and to use the appropriate value accordingly.

7. What is the stress-strain curve for steel?

The stress-strain curve for steel shows the relationship between applied load and elongation during a tensile test. The load values are transformed into stress values and the elongation is transformed into strain to result in a curve that provides important information on the material's behavior under different loading conditions.

A complete stress-strain curve is necessary for the accurate modeling of nonlinear material behavior, such as crash simulations and forming operations. Additionally, finite element analysis (FEA) relies on accurate material descriptions, including the stress-strain curve, especially for nonlinear simulations. This makes a complete stress-strain curve essential for accurate nonlinear FEA material description.

8. Where can I find stress and strain curves for SSAB steel grades?

You can find stress-strain curves for SSAB steel grades on the SSAB website under the "Technical support" section. These curves provide important information about the behavior of SSAB steel grades under different loading conditions and are useful for accurate modeling in applications such as structural design, forming operations and crash simulations. 

To access the stress-strain curves for SSAB steel grades, go to the SSAB website and navigate to the "Technical support" section, where you will find the necessary information to select the appropriate steel grade and access to the complete stress-strain curves. It is important to use accurate material descriptions for modeling and simulation purposes, and the stress-strain curves provided by SSAB can help to ensure accurate and reliable results. 

Also, the SSAB Design Handbook provides detailed information on the mechanical properties of SSAB steel grades, as well as guidelines for material selection, design optimization and forming processes.

9. What is the difference between engineering stress and strain compared to true stress and strain?

The engineering stress-strain data is calculated by using the initial cross-sectional area of the test sample, consequently it neglects the actual area reduction that takes place during elongation. To calculate a more correct value of the stress, the true cross-sectional area for each data point needs to be considered. This means that the true stress is slightly higher than the engineering stress, as the diagram shows.

Engineering stress is defined as the applied force divided by the initial cross-sectional area, F/A0. While true stress is defined as applied force divided by the current cross-sectional area, F/A. Engineering strain is defined as the increase in length divided by the initial length, ΔL/L0. While true strain is defined as dε=dL/L, by integration from L0 to L0+ΔL.

When necking occurs during deformation, the material undergoes significant localized deformation resulting in a heavily reduced cross-sectional area. This can lead to a drop in load-carrying capacity, causing the engineering stress to decrease. However, the true stress, which takes into account the actual area reduction, will continue to increase with increasing strain. Nevertheless, after necking, the true stress-strain curve becomes difficult to measure accurately due to inhomogeneous deformation. This is why different material models are used to describe the true stress-strain behavior after necking, such as the models represented by the dotted line in the diagram below. 

10. How can I convert between MPa and ksi?

Use a conversion factor of 1 MPa ≈ 0.145 ksi to convert between megapascals (MPa) and kilopound per square inch (ksi). To convert from MPa to ksi, multiply the value in MPa by 0.145. To convert from ksi to MPa, divide the value in ksi by 0.145.

MPa and ksi are both commonly used units to measure stress in engineering and materials science. MPa stands for megapascal and is the metric unit of stress, while ksi stands for kilopound per square inch and is the imperial unit of stress. Both units describe the amount of force per unit area. 

11. What is A₅, A₅₀ and A₈₀ elongation?

In materials science and engineering, elongation is a measure of a material's ability to deform under tensile stress. The most common definition is the permanent extension of a test sample after it has fractured in a tensile test. The subscripts 50 and 80 indicate the gauge length expressed in millimeters, while A5 means that the gauge length is for a so-called proportional specimen. Nowadays this is only called A. 

A5, A50, and A80 elongation values are commonly reported in material specifications, quality control documents and research papers. 

12. How do the dimension tolerances influence the material data?

Dimension tolerances refer to the allowable deviation from specified dimensions, such as thickness or width, in a material. These tolerances are typically defined in standards or codes, such as Eurocode, ASTM or ASME, and are important to ensure that the material meets the requirements for a specific application.

The impact of dimension tolerances on material data depends on the specific material properties being measured. In some cases, tolerances may have a minimal effect on the material data, while in other cases even small deviations from the specified dimensions can significantly affect the measured values.

For example, when measuring the mechanical properties, such as tensile strength or elongation, of a material, the test samples must be prepared according to the dimensions and tolerances specified to ensure accurate and repeatable results. If the dimensions are not within the specified tolerance, the material data may be affected by variations in the sample preparation, which can lead to inaccurate or unreliable results.

Similarly, dimension tolerances must be accounted for in the design and fabrication of components to ensure that the final product meets the required specifications and performs as intended. Deviations from the specified tolerances can result in reduced strength or other performance issues, which in turn can impact the overall safety and reliability of the component.

13. Can hardness be converted to yield strength or vice versa?

No, there is no direct conversion between hardness and yield strength. While these two material properties are related, they measure different aspects of a material's behavior.

Hardness is a measure of a material's resistance to localized plastic deformation, often determined by indentation or scratch tests. Yield strength, on the other hand, is the stress at which a material begins to deform plastically. While there may be some correlation between the two properties, they cannot be directly converted without considering other factors.

However, there is a formula for the relation between the ultimate tensile strength and hardness, which provides an approximation of the ultimate tensile strength of a material based on its Brinell hardness: Tensile strength in MPa = 3.2 * Brinell hardness. This formula does not give information about yield strength.

14. What is the difference between strip and plate material?

Both strip, foil, sheet and plate are flat steel products. The thickness and width definitions vary by standards and geography.

In thickness order (thin to thick):

  • Foil. Sold as coils.
  • Strip (narrow width). Sold as slitted coils or cut-to-length sheets.
  • Sheet (wider width). Sold as coils or cut-to-length sheets.
  • Plate. Sold as coils or flat plates.

Strip materials are suitable for applications such as automotive parts, building panels, household appliances, precision components, and springs, where tight tolerances and smooth surfaces are important. Plate materials are often used, for example, in heavy machinery, construction equipment, wear plates, and large structural components, where strength and durability are crucial. The choice between strip and plate materials depends on the specific requirements of the application, such as size, shape, strength, and surface finish. However, there are also overlapping uses in some applications, such as containers and trucks.

15. What is the corrosion resistance?

Corrosion resistance refers to a material's ability to withstand corrosion or degradation caused by environmental factors. There are several common ways to achieve corrosion resistance, including:

  • Protective coatings such as paint, powder coating, and anodizing.
  • Galvanizing and electroplating to apply a layer of protective metal to the surface.
  • Material selection of alloys and metals that are naturally resistant to corrosion

Proper maintenance and cleaning of the material to prevent corrosion buildup.

The need for different corrosion protections varies depending on the application and environment. For example, protective coatings such as paint and powder coating are commonly used for outdoor equipment and structures that are exposed to moisture and other corrosive elements. Galvanizing and electroplating are often used for metal parts and components that are exposed to harsh chemicals or extreme temperatures. Material selection is also critical, with specific alloys and metals chosen for their natural resistance to corrosion in specific environments. Proper maintenance and cleaning of the material is essential to prevent corrosion buildup and ensure long-term protection.

16. What is quenched steel?

Quenched steel is a type of steel that has been heated to a high temperature and then rapidly cooled by quenching in a liquid or gas. This rapid cooling alters the microstructure of the steel to result in a material with increased hardness and strength.

Quenched steel is known for its hardness, wear resistance, and strength. Due to its properties, it is commonly used in mobile cranes, buckets, dumper bodies, trailer chassis, manufacturing of tools, gears, bearings, and other mechanical parts that require high strength and wear resistance.

17. What makes high-strength steel stronger than other steel?

High-strength steel (HSS) is a type of steel that has been engineered to have higher levels of strength and toughness than traditional carbon steel. This is achieved by adjusting the amount of alloying elements, the mechanical and heat treatment procedures used to control the microstructure of the steel. The highest strength levels are typically achieved by using high-temperature heating followed by rapid cooling in water or oil, a process known as quenching.

Different types of HSS and their typical properties include:

  • Dual-phase steel: This type of HSS is characterized by a mixture of ferrite and martensite phases, which provides high strength, good formability and excellent impact resistance. It’s often used in automotive components such as chassis and body parts.
  • Transformation-induced plasticity (TRIP) steel: TRIP steel is characterized by a microstructure that includes retained austenite, which allows it to undergo strain-induced transformation during forming, resulting in increased strength and ductility. It is often used in automotive structural components.
  • Martensitic steel: This type of HSS is characterized by a microstructure of martensite, which provides high strength and hardness. It is often used in applications that require high strength and wear resistance, such as mobile cranes, buckets, scrap fragmentizers, cutting tools and dumper bodies.
  • Boron steel: This type of HSS contains small amounts of boron, which increases hardenability and strength. It is often used in automotive safety components such as door intrusion beams and bumper reinforcements.

Overall, HSS is used in a wide range of applications where high strength and toughness are required, including construction equipment, agricultural machinery, automotive components, and industrial machinery.

18. What is the difference between structural steel and abrasive resistance steel?

In summary, the main difference between structural steel and abrasion-resistant steel is their respective properties and applications. Structural steel usually guarantees a certain yield strength, while abrasion-resistant steel guarantees the hardness of the material. Structural steel is used for its strength and load-bearing capacity in construction and engineering applications, while abrasion-resistant steel is used for its resistance to wear and impact in high-wear applications such as mining, construction, and material handling equipment.

The difference between structural steel and abrasion-resistant steel lies in their respective properties and typical applications.

Structural steel is designed to have a certain yield strength, which is the amount of stress that the steel can withstand before it begins to deform permanently. This property is critical for ensuring the safety and stability of structures such as buildings, cars, trucks, and numerous other applications.

Abrasion-resistant steel, on the other hand, is designed to have high hardness and toughness, which enables it to resist wear and deformation caused by impact and abrasive forces. This property is essential for applications where materials are subjected to repeated impact and wear, such as in yellow goods, mining, and material handling equipment.

19. What is the difference between high strength steel and mild steel?

Mild steel has a low yield strength and is relatively soft and ductile, making it comparably easy to shape and form. It is commonly used in applications where high strength is not the primary concern, such as in construction and the manufacture of household appliances.

High-strength steel, on the other hand, is engineered to have significantly higher strength properties than mild steel, making it suitable for use in applications that require a high strength-to-weight ratio, improved durability, and impact resistance. High-strength steel is used in a wide range of applications, including the construction of bridges and high-rise buildings, automotive and other transport industries, wear plates, and other various industrial machinery and equipment. Overall, the key difference between high-strength steel and mild steel lies in their respective strength and hardness properties, and the applications in which they are used

20. Is high-strength steel stiffer than mild steel?

No, stiffness depends on the Young’s modulus of the material, which is a measure of its resistance to elastic deformation under stress. As all steel grades have the same Young’s modulus, the stiffness of high-strength steel and mild steel is the same.

21. What factors should be considered when designing with high-strength steels?

Designing with high-strength steels is a complex process that requires careful consideration of several factors to achieve optimal performance and safety. One critical factor to consider is the mechanical properties of the material, such as yield strength, tensile strength and ductility, as these significantly impact the structural integrity and load-bearing capacity of the design.

Another critical factor to consider is the type and manner of loading, including static or dynamic loads, and the effects of instability. Dynamic loads, such as fatigue of weld joints, can severely impact the longevity and durability of the structure, making it essential to factor in these loads during the design process.

In addition, high-strength steels may require processing adjustments during fabrication to suit their properties. Also, environmental factors like low temperature, wear and corrosion must be considered to ensure the longevity and performance of the structure. 

To ensure the best possible design, it is important to consult with experts in high-strength steel design and fabrication. This, together with technical support from companies such as SSAB, can provide valuable information and guidance in designing with high-strength steels.

Overall, designing with high-strength steels requires a holistic approach that takes into account various factors and considerations. Utilizing the resources available, such as handbooks and material data, and the expertise of steel companies like SSAB can help to ensure the successful and safe use of high-strength steels in structural design. 

The information in this report is only applicable to SSAB’s products and should not be applied to any other products than original SSAB products. 

This report provides general results and recommendations for SSAB steel products. This report is subject to SSAB’s Terms of Use. It shall be the user's responsibility to verify that the information contained herein is correct and is suitable to be used for the particular purpose and application of the user. The report is intended to be used by professional users only who possess adequate expertise, qualification and knowledge for the safe and correct use of the results and recommendations in this report. This report is provided “as is”. The use of the report is at user’s own discretion and risk and that users will be solely responsible for any use of this report. SSAB disclaims any liability for the content or potential errors of this report, including but not limited to warranties and condition of merchantability or fitness for a particular purpose or suitability for individual applications. SSAB shall not be liable for any kind of direct or indirect damages and/or costs related to or arising therefrom, whether special, incidental, consequential or directly or indirectly related to the use of, or the inability to use, the report or the content, information or results included therein.