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High-strength steel plates for construction machinery

High-strength steel plates for construction machinery

High-strength steel plates for construction machinery are specifically developed to meet the structural requirements of excavators, loaders, cranes, bulldozers, and other construction machinery under high-intensity operations and complex working conditions (such as heavy loads, impact, wear, and corrosion). Their core characteristics lie in their excellent mechanical properties (strength and toughness) combined with good processability (welding and forming), significantly reducing equipment weight, increasing structural load-bearing capacity, and extending service life. They are a key material for achieving lightweight and high-performance performance in modern construction machinery.

Classification :

Thick steel plate

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E-mail : lily@iron-element.com

PRODUCT DETAILS

Product introduction

Main specifications

1. Thin gauge (2-12mm): Suitable for components subject to low stress or requiring bending and forming, such as cab frames (Q345D, 3-5mm thickness) and crane jib connecting plates (Q690D, 8-12mm thickness).

2. Medium gauge (14-30mm): Suitable for mainstream load-bearing structural components, such as excavator frames (Q460D, 16-20mm thickness) and medium-sized crane main booms (Q960D, 20-25mm thickness).

3. Thick (32-100mm): Suitable for extremely heavy-loaded or easily worn parts, such as the bucket bottom of mining excavators (NM500, 50-60mm thick) and the fixed boom of large cranes (Q1100D, 40-50mm thick).

4. Extra-thick (100mm and above): Rarely used in conventional construction machinery, it is only suitable for very large equipment (such as the boom base of mining excavators over 300 tons, Q1300D, 120-150mm thick).

Note: Thickness tolerance must comply with standards (e.g., GB/T 709-2019, "Dimensions, Shape, Weight and Permissible Deviations of Hot-Rolled Steel Plates and Strip"). Generally, the thickness tolerance for medium and thick plates (≥4mm) is ±0.3mm to ±1.2mm (adjusted according to the thickness range).

Core features

Functional category	Specific requirements	Adapt to the scene
Mechanical properties	1.High strength：Yield strength (σs) is usually ≥345MPa, and high-end models can reach over 1500MPa, which can withstand heavy loads without deformation; 2. High toughness：Low-temperature impact energy (Akv at -40°C) ≥ 27J, to avoid brittle cracking of steel plates during low-temperature operations (such as winter in northern China); 3. Good fatigue performance：Resist long-term cyclic stress (such as repeated lifting and lowering of the boom) and reduce the risk of structural fatigue failure.	The bucket bears the impact of ore and the crane arm carries heavy objects
Processing performance	Excellent weldability：Most engineering machinery structures are welded structures, which require steel plates to have low welding crack sensitivity (such as carbon equivalent Ceq ≤ 0.45%) and to maintain performance without complex heat treatment after welding; Formability：It can be processed into complex structures (such as arc-shaped arms) through bending, stamping and other processes, and its performance is stable after forming.	Frame welding and assembly, bucket arc wall forming
Environmental adaptability	1. Wear resistance：Higher surface hardness (such as HB300-HB500) or improved wear resistance through alloy design to extend the service life of buckets and track shoes; 2. Corrosion resistance：Some models have added elements such as Cu and Cr, or have undergone surface treatment (such as weathering steel) to adapt to corrosive environments such as mines and wetlands.	Buckets for mining operations and track shoes for wetland dozers

Grade-marine plate mechanical properties

Strength level	Yield strength range（MPa）	Grade	Applicable parts
Medium to high intensity	345-690	Q345、Q460、Q690（国标）；S355、S460（欧标）	Construction machinery frames, cab frames (structural parts with less stress)
High strength	700-960	Q960（国标）；S960（欧标）、WELDOX 960（瑞典 SSAB）	Crane boom, excavator boom (core load-bearing structure)
Ultra high strength	≥1000	Q1100、Q1300、Q1500（国标）；WELDOX 1100、DOMEX 1500（国际）	Heavy excavator buckets, large crane telescopic arms (extremely heavy-duty components)

Production process

1. Refining and Smelting: Utilizing a converter + LF (ladle refining furnace) + RH (vacuum degassing) process, this process reduces harmful elements such as S and P in the steel (S ≤ 0.005%, P ≤ 0.015%), reduces non-metallic inclusions, and improves steel purity (purity directly impacts toughness and weldability).

2. Controlled Rolling and Controlled Cooling (TMCP): High-temperature rolling combined with rapid cooling is used to control the steel plate microstructure.

High-temperature rolling refines the austenite grains.

Immediately after rolling, rapid cooling is achieved through laminar cooling to inhibit grain growth and form a fine-grained ferrite, bainite, or martensite structure (a fine-grained structure is key to achieving both strength and toughness).

3. Quenching and Tempering (Quenching + Tempering): Ultra-high-strength steel plates (such as Q960 and above) require an additional "quenching + high-temperature tempering" process:

Quenching: The steel plate is heated to above Ac3 (typically 850-950°C), held at this temperature, and then rapidly water-cooled to achieve a high-strength martensite structure.

Tempering: The quenched steel plate is heated to 350-600°C to eliminate internal stresses and reduce brittleness while retaining the high strength of the martensite. The resulting structure is "tempered martensite + bainite," achieving a balance of ultra-high strength and high toughness.

Company Strength

We strictly inspect the quality,our products are reasonably priced , we have stable supply，fast deliver and responsible after-sale service, so our products and service are widelv praised ov our cusomer.