What is the best steel cutting method?

There is no single best method. The most commonly applied compromise is probably oxy-fuel cutting. Factors to consider are plate thickness, required tolerances, cut edge quality, plate hardness, heat influence, cost, available equipment. SSAB Tech Support can give detailed advice. Indicative choice of cutting method for different plate thickness ranges: Thinner than 2 mm: Laser cutting. Thinner than 3 mm: Plasma or laser cutting. Thinner than 10 mm: Waterjet, plasma or laser cutting. Thicker than 10 mm: Laser, plasma, oxy-fuel or waterjet cutting. Thicker than 30 mm: Plasma, oxy-fuel or waterjet cutting. Thicker than 50 mm: Oxy-fuel or waterjet cutting.

How do I choose a steel cutting method?

When choosing a cutting method, it is good to know that a number of methods can be used for a particular situation. When choosing the cutting method, you should consider the thickness of the plate, cut edge quality and costs. For more information or assistance in choosing the right cutting method for your business’s needs, contact SSAB Tech Support . Indicative choice of cutting method for different plate thickness ranges: Thinner than 2 mm: Use laser cutting. Thinner than 3 mm: Use plasma or laser cutting. Thinner than 10 mm: Use waterjet, plasma or laser cutting. Thicker than 10 mm: Use laser, plasma, oxy-fuel or waterjet cutting. Thicker than 30 mm: Use plasma, oxy-fuel or waterjet cutting. Thicker than 50 mm: Use oxy-fuel or waterjet cutting.

What is preheating of steel?

Preheating steel before cutting increases the temperature in the vicinity of the cut during the actual process. This will reduce the risk for hydrogen-induced cracking in particular for high-strength/hard steel. The maximum temperature allowed greatly depends on the steel grade. Too high temperature may destroy the steel properties.

Is it necessary to preheat before cutting steel?

The purpose of preheating is normally to reduce the risk for hydrogen-induced cracking when applying thermal cutting methods. This risk grows with increasing plate thickness and hardness of the steel plates to be cut. This makes preheating an important factor to consider when cutting Hardox ® and most Strenx ® grades. Detailed recommendations can be found in the SSAB brochures found at SSAB Download center.

How to preheat before thermal cutting?

Preparing steel correctly before thermal cutting is essential for achieving safe, predictable, and high‑quality results. This site brings together SSAB’s best practices for preheating—why it matters, when it’s required, and how to do it effectively. From choosing the right heating method to understanding temperature and soaking‑time requirements for different steel grades, you’ll find clear, practical guidance designed to support reliable cutting performance and protect material integrity.

Understanding when preheating is needed in welding and thermal cutting

One of the most common questions we receive from customers is whether preheating is required before welding or thermal cutting. Because the answer depends on material behavior, plate thickness, and heat input, SSAB has developed its own rigorous test procedures to determine when preheating is necessary—and when it isn’t.

In the two videos below, Welding Specialist Petter Eklöf and Thermal Cutting Specialist Sedin Vilic share SSAB’s approach to evaluating preheating requirements.

Preheating in theory

Preheating in practice

Preheating methods

One effective method to prevent hydrogen cracking during cutting is preheating the material. Preheating allows more hydrogen to diffuse away from the cut edge and reduces the cooling speed of the cut edge, thus minimizing introduced tensile stresses. Preheating is particularly beneficial before oxy-fuel cutting and plasma cutting with oxygen as plasma gas. However, for all types of laser cutting and plasma cutting with nitrogen, preheating is not recommended due to its negative effect on the cut edge quality. Depending on the situation, either part of the plate or the entire plate can be heated.

The most common ways to preheat the plate are preheating furnaces, preheating lances, and electrical mats.

Preheating furnaces

Preheating in furnaces is the best way to preheat the plate, since it ensures even temperature distribution across the entire plate.

Preheating lances

Preheating lances can also be used for preheating Hardox^® wear plate. It is crucial to keep the lances in motion to prevent the temperature of the wear plate from exceeding the maximum preheating temperature. Additionally, the preheating temperature should be measured on the opposite side of where the preheating is applied.

Preheating with electrical mats

Electrical mats offer a convenient preheating method with precise temperature control. They can be used to preheat the plate on the floor, on a cutting table, or for improved usability in an improvised furnace. Since electrical mats provide slow preheating, a recommended practice is to preheat overnight to achieve temperatures of 150-200 °C (302-392 °F) before commencing the cutting operation the next morning.

Electrical mat

Electrical mats and improvised furnace

Preheating temperature recommendations

Preheating soaking time recommendations

Achieving effective preheating requires ensuring that the entire cross-section of the plate reaches the target temperature. A certain amount of time is needed for the heat to spread uniformly throughout the plate. This requirement applies generally to preheating, regardless of the steel grade.

It's important to maintain the surface at the target temperature consistently throughout the soaking period. For instance, if preheating a 100 mm plate to 175 °C from both sides, once the surface temperature of 175 °C is reached, it should be sustained for 11 minutes to ensure the core of the plate attains the same temperature, as shown in the graphs below.

Required soaking time when heat is applied from both sides, for example heating in a furnace

Required soaking time when the heat is supplied from one side only, for example, heating with propane torches or heating with electrical mats

FAQs about cutting

More questions and answers about cutting

Master the next step in precision cutting

Proper planning sets the foundation, but true cut quality depends on selecting the right thermal‑cutting method. Explore the characteristics, capabilities, and best‑practice parameters for each process to ensure consistent performance in high‑strength steels.

Proceed to process‑specific cutting parameters

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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.