Planning and preparation
Essential guidance for achieving high‑quality thermal cutting of SSAB steels. Here you’ll find best practices for nesting parts efficiently, preparing for both oxy‑fuel and plasma cutting, and applying the correct preheating methods. The combined information helps you plan safer operations, protect material properties, and ensure consistent cutting performance across all stages of the process.
How to nest for cutting?
The purpose of nesting is to maximize material utilization and minimize cutting time in order to improve productivity. This can be achieved using a variety of specialized nesting software tools. In addition, most cutting machine manufacturers provide their own software solutions. Nesting can be done directly on the machine or on a separate computer, with the resulting cutting code transferred to the machine.
When cutting high-strength steels, nesting becomes even more critical, as improper nesting can lead to undesirable effects such as softening of cut parts or distortion caused by the relaxation of internal stresses.
Softening of cut parts
This issue is especially relevant for Hardox® steels, which derive their exceptional wear resistance from their high hardness. These materials have a relatively low tempering temperature—meaning, if heated above a certain threshold, they can lose their hardness.
These maximum allowable temperatures are listed in the Cutting of Hardox® brochure and in the CutCalc application, see also Preheating temperature recommendations. For example, if all parts are cut from one end of the plate in sequence, the first piece will maintain its hardness. However, the heat introduced into the plate during that first cut will raise the overall temperature of the surrounding area. As a result, the second piece—cut immediately afterward and nearby—may experience slight softening, while subsequent parts are at an even higher risk of losing hardness. Always monitor the plate temperature, especially when cutting small parts, as they can heat up rapidly and lose hardness more easily.
To avoid this, heat input during cutting must be evenly distributed across the plate. This means that after cutting a part from one corner of the plate, the next part should either be cut from the opposite corner or delayed until the plate has cooled sufficiently.
Example of nesting in ProNest software.
Distortion due to internal stress relaxation
Distortion, or warping, can occur when internal stresses are unevenly relieved due to localized heating. This typically happens when several cuts are made in close proximity without proper planning.To minimize this effect, nesting and cutting sequences should be designed to maintain thermal balance across the plate. In other words, parts should be cut in a symmetrical and staggered order to prevent localized stress release.
Proper nesting is not only about saving material—it's a critical step in preserving the mechanical properties of high-strength steels and ensuring dimensional accuracy. A well-planned nesting strategy leads to higher quality, longer-lasting parts, and fewer reworks.
How to prepare for oxy fuel cutting?
Before starting an oxy-fuel cutting operation, it is essential to ensure that all equipment is in proper working condition. This includes checking gas cylinders, pressure regulators, valves, and hoses for any signs of damage or leaks.
Personal protective equipment (PPE) must always be worn—this includes flame-resistant clothing, safety glasses, gloves, and other appropriate gear to ensure operator safety.
Material temperature requirements for high-strength steels
When cutting high-strength and wear-resistant steels, such as those produced by SSAB, the plate should be at room temperature unless otherwise specified in the material recommendations.
If the plates have been stored outdoors or in unheated areas where ambient temperatures drop significantly below room temperature, they must be preheated to room temperature before cutting—unless a higher preheat temperature is explicitly required.
If preheating is recommended, it is important to verify that the desired preheat temperature has been reached throughout the entire thickness of the plate. This can be done by measuring the temperature on the opposite side of the plate from where the heat is being applied.
How to prepare for plasma cutting?
Similar to oxy-fuel cutting, plasma cutting requires proper preparation before starting the process. This preparation includes checking the condition of the equipment, addressing safety considerations, and ensuring the conditions are right for achieving high-quality cuts.
Plasma cutting generates an electric arc, similar to welding, which produces intense light capable of damaging both eyesight and skin. Therefore, it is crucial to wear appropriate personal protective equipment (PPE), such as a welding helmet with the correct shade, gloves, and flame-resistant clothing.
Additionally, plasma cutting produces significant amounts of fumes and dust. It is essential to use proper ventilation or fume extraction systems. A highly effective method is cutting partially or fully submerged in water, which significantly reduces airborne particulates and improves working conditions.
When cutting high-strength or wear-resistant steels, make sure the plate is at room temperature before cutting. If the material has been stored outdoors or in cold environments, it must be preheated to room temperature.
For steels that require specific preheating temperatures (as per SSAB’s recommendations), the plate must be preheated accordingly before cutting begins.
One of the key factors in plasma cutting is proper grounding. The ground (return) clamp must be securely connected directly to the plate being cut. Poor grounding can result in unstable arc behavior and poor cut quality.
Unlike oxy-fuel cutting, plasma cutting is more sensitive to the surface condition of the material. It is important to remove rust, scale, oil, and any foreign particles from the surface of the plate, as these can negatively affect arc stability and cut quality.
Use the correct consumables—nozzles, electrodes, and shield caps—based on the material thickness and steel type. These are specified by the plasma system manufacturer.For SSAB steels, the same consumables and settings as for mild steel can generally be used. However, fine-tuning of parameters such as cutting speed, amperage, and gas flow may be required to achieve optimal results.
Proper preparation ensures safer operation, better cut quality, and longer consumable life—especially when working with high-performance steels.
How to preheat before thermal cutting?
Preheating is an important step when thermal cutting high‑strength steels, helping reduce cracking risks and ensuring consistent cut quality. SSAB’s guidance explains when preheating is needed, how to choose the right method, and how to reach the correct temperature throughout the plate. From furnaces and heating lances to electrical mats, along with clear temperature and soaking‑time recommendations, these pages give fabricators the essential practices for safe and reliable cutting.
FAQs 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.
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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.
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