Steel Clad Plate Research Articles

A Review on Metallurgical Issues in the Production and Welding Processes of Clad Steels.

Carbon and low-alloy steel plates clad with stainless steel or other metals are a good choice to meet the demand for cost-effective materials to be used in many corrosive environments. Numerous technical solutions are developed for the production of clad steel plates, as well as for their joining by fusion welding. For thick plates, a careful strategy is required in carrying out the multiple passes and in choosing the most suitable filler metals, having to take into account the composition of the base metal and the cladding layer. The specificity of the different processes and materials involved requires an adequate approach in the study of the metallurgical characteristics of clad steel, thus arousing the interest of researchers. Focusing mainly on ferritic steel plates clad with austenitic steel, this article aims to review the scientific literature of recent years which deals with both the production and the fusion welding processes. The metallurgical issues concerning the interfaces and the effects of microstructural characteristics on mechanical behaviour and corrosion resistance will be addressed; in particular, the effects on the fusion and thermally affected zones that form during the fusion welding and weld overlay processes will be analysed and discussed.

Effect of Heat Treatments on the Microstructure and Mechanical Properties of SS317L/ASTM SA516 GR60 Steel Clad Plate Fabricated Through Hot Roll Bonding

Triple-layer stainless-steel clad plate having 317L stainless steel (SS317L) as cladding layer and ASTM SA516 GR60 (GR60) as backing layer was successfully fabricated through vacuum hot roll bonding (VHRB) at 1373 K (1100 °C) temperature and strain rate regime of 1–5 s−1, which were identified through process efficiency maps of the base materials (SS317L and GR60). The process efficiency maps were constructed by conducting isothermal compression tests within the temperature range of 1173 K (900 °C)–1473 K (1200 °C) and 0.1–50 s−1strain rate regime. Effect of post-rolling heat treatments on the mechanical properties of clad plate was studied after solutionization at 1173 K (900 °C) for 1 h followed by cooling at different rates, i.e., water quenching, air cooling, and furnace cooling. As compared to other post-rolling heat treatments, the ultimate tensile strength, uniform plastic elongation, and maximum shear strength showed a significant change from 524 MPa, 0.46 and 519 MPa to 652 MPa, 0.36 and 410 MPa, when the normalized clad plate was solutionized at 1173 K (900 °C) and water quenched. A drastic change in shear fracture mode from gradual failure in normalized condition to catastrophic failure was also noticed after water quenching. These changes are essentially manifestation of the microstructural change in GR60 layer which led to the change in mechanical properties.

Research status and application of 304/Q235 stainless steel clad plate

Research status and application of 304/Q235 stainless steel clad plate

High bonding strength of Ti /steel clad plates prepared by a developed electromagnetic induction heating followed by rolling

Titanium/steel clad plates exhibit significant potential for industrial applications, such as petrochemical and aerospace, due to their combined advantages of two components. In the conventional hot rolling process, the formation of brittle intermetallic compounds (IMCs) had a detrimental effect on the mechanical properties of Ti/steel clad plates. Therefore, the present study proposed an electromagnetic induction heating rolling (EIHR) technique for efficiently fabricating Ti/steel clad plates with high bonding strength at a relatively low temperature, while avoiding the formation of brittle IMCs. Additionally, a pure iron DT4 interlayer with good fluidity was introduced between Ti and steel, which can further enhance both the interface bonding strength and elongation of the clad plates. Based on the electron backscattered diffraction characterization results of the interface, it was found that the addition a DT4 interlayer facilitated dynamic recrystallization of steel side and led to a reduction in dislocation density. Moreover, a pronounced {100}〈011〉 rotational cube texture was evident on the (100) pole figures as a result of substantial plastic deformation during the rolling process. Finally, the relationship between interface microstructure and mechanical performance was established.

A new experimental methodology for investigating the impact of subsequent welding passes on the properties of the austenitic stainless clad steel plates welded joint: part I – a substrate case study

In this study, the influence of the applying repeated thermal cycling during welding on the microstructural transformations and mechanical properties in Austenitic Stainless Clad-Steel Plates (ASCSP) has been investigated, particularly in the substrate. For this purpose, a novel methodology was used, by filling the entire groove length and gradually shortening the subsequent passes. Afterwards, microstructural characterization of different zones in the welded joint was conducted using optical microscope. Results showed a decrease in acicular ferrite (AF) in the Weld Metal Substrate (WM-S) from the root pass (10 kJ/cm) to the second pass (13.5 kJ/cm). This decrease continued until a total disappearance by the third pass due to a heat input of 17.8 kJ/cm. Vickers micro-hardness test was used to investigate the effect of the subsequent passes on the mechanical properties of the joint. Micro-hardness examination confirms the metallurgical results. It was revealed that micro-hardness variations are influenced by AF percentage and pro-eutectoid ferrite levels.

Single-pass high-power laser-Arc hybrid welding of thick stainless steel clad plates: Microstructure and mechanical properties

In order to solve the existing problem of low efficiency of multi-layer and multi-pass welding methods for thick stainless steel clad plate (SSCP), this paper proposes high-power laser-arc hybrid welding (HP-LAHW) single-pass weld thick SSCP. The effects of wire feeding rate (WFR) on the weld's composition distribution, microstructure and mechanical properties were investigated. The weld morphology is nail-shaped, consisting of a wide arc zone (ArcZ) within the stainless steel layer and a long narrow laser zone (LaserZ), mainly in the carbon steel layer. With the increase of WFR, the dilution rate of the carbon steel layer to the ArcZ decreases first and then increases. The influence of WFR on the microstructure and mechanical properties of the weld is observed mainly in the ArcZ. When the WFR reaches 6 m/min, the composition of the microstructure within the ArcZ will change from martensite, ferrite, and a small amount of granular austenite to ferrite and a small amount of austenite, resulting in the microhardness of the ArcZ decreasing rapidly from 398 HV to 210 HV. The solidification type and microstructure transformation mechanisms within the weld were elucidated based on quantitative calculations of the chromium and nickel equivalent ratios. The microstructure of the LaserZ in all welds is predominantly martensitic due to the rapid cooling rate, which makes the tensile properties of the weld higher than the base metal (BM). The results of this study provide technical support for realizing high-efficiency and high-performance single-pass HP-LAHW of thick SSCP.

Microstructure Evolution and Deformation Behavior of High Strength Titanium Clad Steel Plate in the Thermal Compression

This research involves conducting unidirectional axial thermal compression experiments on high‐strength titanium‐clad steel plates (TCSPs) at different temperatures and strain rates. Thermally compressed samples are evaluated for macromorphology, microstructure, macroscopic texture, and dislocation density. Deformation consistency is observed in α‐titanium under certain conditions, but not in β‐titanium. Pearlite is the main deformation microstructure near the steel interface, expanding with temperature. Striped grain clusters are observed in the α‐titanium near the interface, enhancing deformation uniformity; furthermore, the prevalence of striped grains increases with higher strain rates. However, dynamic recrystallization in β‐titanium hinderes deformation consistency. The fiber presence of texture <111>//ND ensures consistent deformation consistency, whereas the plate texture {0001} <100> in the α‐titanium encourages it. During the deformation process at a consistent rate of strain, it is observed that both matrices initially exhibit a rise, followed by a decline in dislocation density as the temperature increases, peaking at 850 °C. Dislocation density rises as strain rate increases, while temperature remaines constant. At temperatures exceeding 850 °C, bonding strengths decrease with deformation rate and remain comparable. Bonding strengths decreases at 800 °C due to intermetallic compound formation.

Effect of Nb interlayer thickness on interfacial products and mechanical properties of Ti–6Al–4V/EH690 steel clad plate by vacuum hot rolling

The high content of alloying elements in Ti alloys and high-strength steels, combined with the requirement for quenching and tempering heat treatment during the fabrication process of the clad plate, leads to complex interfacial products and poor bonding properties. An Nb interlayer was introduced to enhance the mechanical properties of Ti alloy/steel clad plates. This work investigated the effect of Nb interlayers with initial thicknesses of 10, 25, and 50 μm on the evolution of interfacial products and bonding properties. The results indicated that when the interlayer was thin (10 μm thick), the diffusion of Ti, Fe, and C in the matrix and clad materials could not be completely inhibited due to the uneven distribution of the Nb interlayer at the interface. TiC, NbC, Nb2C, and Fe2Nb were detected at the Nb/steel interface. With the thickness of the interlayer increased (reaching 25 μm or 50 μm), the influence of uneven deformation on the interlayer was weakened, and the Nb/steel interface was composed of Nb2C and Fe2Nb. The tensile shear test indicated that the fracture occurred at the Nb/steel interface and the Nb interlayer. The plasticity of the micrometer Nb interlayer decreased with the increase in interlayer thickness. Therefore, more cracks and brittle fracture characteristics were observed in the fracture surface of the 50 μm thick Nb interlayer sample. The clad interface with a 25 μm thick Nb interlayer exhibited the highest interfacial shear strength of 295 MPa due to the few intermetallic compounds (IMCs) at the Nb/Steel interface and the excellent plasticity of the Nb interlayer.

Evaluation of the Bond Quality of Metal-Clad Plates Using Laser Ultrasonic Local Resonance

The effective detection of delamination defects, especially sub-millimeter delamination defects, in metal-clad plates is of great significance in improving product quality. In this work, the laser ultrasonic (LU) local resonance method is used to locate and characterize the sub-millimeter defects in stainless/carbon steel-clad plates. The influence of the delamination radius on the amplitude and resonant frequency of the laser ultrasound was investigated using 2D axisymmetric finite element (FE) simulations. The simulation results show that both the amplitude and the first resonance frequency (FRF) are effective features for detecting large-scale delamination defects, but the FRF is a better feature for detecting tiny delamination defects. A 304/Q235/304-clad plate specimen was made through a hot rolling bonding process, which contained a large number of self-forming delamination defects. The laser ultrasonic signals of different composite states collected in the experiment have good consistency with the simulated waveforms. The experimental results show that the laser ultrasonic local resonance method is a high-resolution imaging method, which can locate and characterize the sub-millimeter delamination defects in stainless/carbon steel-clad plates.

29-Year SCC Resistance of Liquid Ammonia Tank Using Surface Softened Clad Steel Plates

29-Year SCC Resistance of Liquid Ammonia Tank Using Surface Softened Clad Steel Plates

Axial compressive behavior of high-strength steel-UHPC-clad steel composite walls

This paper proposed a novel high-strength steel-UHPC-clad steel composite wall (HS-UHPC-CS composite wall) and investigated its axial compressive behavior through experimental and numerical methods. A total of 18 axial compressive tests and finite element (FE) analyses, including parametric studies of 120 cases, were conducted. It was shown that the stud spacing-to-plate thickness ratio and the normalized slenderness ratio notably affected the strength and local buckling, while their influence on the initial stiffness was minor. The strength and initial stiffness were improved, while the ductility was compromised by the presence of ultra-high-performance concrete (UHPC). Steel fiber was critical to the HS-UHPC-CS composite wall, while the lack of steel fiber could trigger premature brittle failure. The influence of the strength of concrete was higher compared to steel plate. The critical buckling stress of the steel plate was calculated using Euler's buckling formula for the clad steel plate of the HS-UHPC-CS composite wall. The results were compared with the ordinary composite wall database. In addition, strength from test results, FE results, and the database were compared were compared with strength calculated by design provisions. It was found that the calculated strength was close but not safe. It was recommended that different concrete contribution coefficients should be applied for HS-UHPC-CS composite walls with different normalized slenderness ratios.

Research on short process rolling of high performance wear resistant steel/carbon steel clad plate

An innovative short process rolling has been proposed to produce high performance clad plates of wear-resistant steel/carbon steel with lower production costs. The NM400 and Q345B cast billet instead of traditional hot-rolled plates were chosen to prepare composite steel ingots. The interface morphology, microstructure, and mechanical properties of clad plates with 45%, 60%, and 70% reduction ratios were analyzed and detailed using metallographic microscopy, scanning electron microscopy, and energy dispersive spectroscopy. The results demonstrate that the improvement of the reduction ratio effectively promotes the grain refinement of clad plates and the metallurgical bonding of dissimilar metals. The bonding interface of the clad plate is straight and clear when the reduction ratio is 70%, the distribution of alloy elements is uniform, and the grain refinement is apparent. The tensile strength of the clad plate rolling by the short process rolling reaches 626 MPa, the bonding strength reaches 484 MPa, and the elongation reaches 21%. These results exceed national, international, and industry standards.

Integration for coaxial irradiation of fiber laser, oxygen jet, and oxy-fuel gas

This study introduces a convergence approach named laser oxyfuel and oxy-flame hybrid (LOXAFH) cutting, integrating laser cutting and oxyfuel cutting techniques for cutting clad steel plates. The LOXAFH method combines laser, oxyflame, and oxygen jet in a coaxial manner, harnessing 1 kW power concentration. The LOXAFH cutting head was meticulously developed on the basis of a ray transfer matrix and estimated refractive index by incompressible flow with a computational fluid dynamics program and an optical design program. The LOXAFH cutting is validated through three experiments on 15 mm clad steel plates: oxyfuel cutting, laser-assisted oxygen cutting (LASOX), and LOXAFH cutting.

Microstructures and intergranular corrosion resistances of hot-rolled austenitic stainless steel clad plates

In this study, two stainless steel clad plates (STS 316L/A516-70N and STS 304L/A516-70N) were fabricated without Ni interlayers by hot rolling and normalizing under the same conditions, and their microstructures and intergranular corrosion resistances were comparatively evaluated. Although a similar amount of C diffused from carbon steel to stainless steel during clad fabrication, the thickness of the grain-boundary carburized layer was thinner in STS 316L due to Mo atoms segregated at the grain boundaries. The stainless steel parts of both clad plates had carbides even at their free surfaces and STS 304L also had some amount of δ ferrite. Nevertheless, the corrosion resistance of the free surfaces of both stainless steels was not undermined.

Effect of Nb interlayer on microstructure and property of Ti-6Al-4V/690 MPa grade steel clad plate by vacuum rolling

Ti alloy clad plate is of great interest for marine and petrochemical industry applications. However, high interfacial bonding is hardly obtained in the Ti alloy clad plate due to the brittle intermetallic compounds (IMCs) forming at the interface. In this study, a Ti-6Al-4V alloy/EH690 steel clad plate was fabricated by vacuum rolling and subsequently tempered to control the mechanical property of the steel substrate. The tempered sorbite appeared in the EH690 steel after quenching and tempering (QT). A decarburized zone, Fe2Ti + TiC mixed phases layer, and β-Ti layer were formed at the interface between steel and Ti. The brittle IMCs with high lattice mismatch resulted in a low interfacial strength of 108 MPa. To improve bonding strength, Nb was inserted between Ti and steel as an interlayer, which effectively inhibited the inter-diffusion of Ti, Fe, and C without brittle TiC or Fe-Ti IMCs. A (Ti, Nb) solid solution layer with high plasticity was present at the Nb/Ti interface. Fe2Nb and Fe7Nb6 phases were detected at the steel/Nb interface, exhibiting less brittleness and hardness compared to Fe-Ti IMCs. The interfacial shear strength was up to 265 MPa after adding the Nb interlayer, showing a mixed fracture mode of brittleness and ductility.

Deformation mechanism and microstructure evolution in stainless steel clad plate of longitudinal corrugated hot rolling

Deformation mechanism and microstructure evolution in stainless steel clad plate of longitudinal corrugated hot rolling

Effect of Heat Treatment on Crevice Corrosion Behavior of 304 Stainless Steel Clad Plate in Seawater Environment.

With the application of stainless steel clad plate (SSCP)-enlarging in the marine engineering field, awareness of the consequences of heat treatment on ameliorating microstructure and mechanical properties in stainless steel (SS)/carbon steel (CS) joints is being raised. However, carbide diffusion from a CS substrate to SS cladding may damage the corrosion resistance during inappropriate heating. In this paper, the corrosion behavior of a hot rolling-produced stainless steel clad plate (SSCP) after quenching and tempering (Q-T) treatment, especially crevice corrosion, was studied by electrochemical and morphological methods, such as cyclic potentiodynamic polarization (CPP), confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM). Q-T treatment led to more significance in carbon atoms diffusion and carbide precipitation, which made the passive film of the SS cladding surface on the SSCP unstable. Subsequently, a device for measuring the crevice corrosion performance of SS cladding was designed; the Q-T-treated cladding showed lower re-passivation potential (-585 mV) during CPP when compared to as-rolled (-522 mV), with the maximum corrosion depth ranging from 70.1 μm to 150.2 μm. In addition, the processing of crevice corrosion on SS cladding could be divided into three parts, including the initiation, propagation and development stages, which were driven by the interactions between corrosive media and carbides. The generation and growth mechanism of corrosive pits in crevices were revealed.

The evolution behavior and constitution characteristics of interfacial oxides in the hot-rolled stainless steel clad plate

The interface oxides’ morphologies, compositions and structures of 316 L/Q235 stainless steel clad plate with different vacuum degrees of 105, 400,10 and 10−2 Pa were investigated. As the vacuum degree raises, the oxides changes from continuous coarse nodules to refined rod particles, and the constitution changes from Cr2O3, MnCr2O4 and SiO2 into amorphous Mn2SiO4. Interestingly, the shear fracture position transfers from the interface into the decarburized layer as the vacuum degree increases. Overall, the dispersed nanoscale amorphous Mn2SiO4 play an important role in strengthening and toughening interface of hot-rolled stainless steel clad plates.

An innovative process of clad teeming and rolling for preparing stainless steel/carbon steel clad plate

An innovative process of clad teeming and rolling (CTR) is proposed to prepare stainless steel/carbon steel clad plate. A 20 kg clad ingot was prepared by pouring carbon steel melt around stainless steel core. It was rolled into a clad plate with total reduction ratio of 62.1%. Interfacial morphologies and mechanical properties were studied before and after hot rolling. Interfacial element diffusion was analyzed and the carbide phases were identified by XRD. The result shows that an excellent bond interface is obtained by clad teeming. The interfacial shear strength reaches 242 MPa in as-cast clad ingot. A chromized zone containing large amount of chromium-rich M7C3 carbides and a decarburized zone form in carbon steel substrate. A carburized zone containing small amount of M23C6 carbides occurs in stainless steel layer. The interface defects are quickly eliminated by the first rolling pass. The interfacial shear strength further increases to 353 MPa after hot rolling of four passes.

Interfacial gradient M7C3 carbides precipitation behavior and strengthening mechanisms of stainless steel/carbon steel clad plates

The mechanical incompatibilities between ferrite and martensite at the cladding interface of stainless steel (SS)/carbon steel (CS) clad plates can result in stress concentration and interface cracks. In this paper, 304 SS/Q235 CS clad plates were prepared by liquid-solid (L-S) composite casting, and the mechanical incompatibilities between ferrite and martensite reduced by constructing gradient carbides in the interfacial ferrite. The precipitation behavior of the gradient carbides was analyzed, and the strengthening mechanism was revealed. The ultimate strength of the SS/CS clad plates was 370 MPa when stretched perpendicular to the cladding interface, and the SS/CS clad plates fractured in the CS that was far from the cladding interface. The interfacial microstructures from the CS to the SS were ferrite, M7C3 carbides, and lath martensite, and the carbides content gradually decreased toward the CS. During the L-S composite process, a micro-melting region with decreased volume fraction of interdendritic liquid to the CS formed at the cladding interface. The C, Cr, and Ni mixed and diffused in the interdendritic liquid, and the gradient distribution of elements resulted in the precipitation of coherent M7C3 carbides whose volume fraction decreased toward the CS. The coherent strengthening and precipitation strengthening of carbides strengthened the interfacial ferrite and resulted in a gradient strengthening, which reduced the mechanical incompatibilities between ferrite and martensite at the cladding interface. Additionally, the gradient carbides changed the stress state at the cladding interface and improved the interfacial bonding strength.