CN108951859A - Using the construction steel structure composite node of CrNiMn high alloy wlding and cast welding construction - Google Patents

Abstract

Composite joints of building steel structures using CrNiMn high-alloy welding consumables and cast-welded construction. The invention solves the problems of unsatisfactory weldability between cast steel and hot-rolled steel steel members of two different materials, complicated construction techniques for dissimilar steel welding, and hidden dangers of welded joint quality that are likely to occur during on-site installation and welding construction. The joints of the cast steel main body member and the extension members of the structural main body are arranged in equal numbers, the free ends of the joints of the cast steel main body members are welded together with the corresponding extension members of the structural main body, and the free ends of the joints of the cast steel main body members are connected with the corresponding transverse extension members of the structural main body. The dimensions of the outer contour of the section are set to be the same, and the material of the extension member of the main structure is set to be the same as that of the main member of the structure. The invention converts the dissimilar steel welding connection process between the cast steel node body component and the structural main component in the on-site steel structure installation and construction into the butt welding of the structural steel components of the same material between the structural main component and the structural main extension component.

Description

Composite joints of building steel structures using CrNiMn high-alloy welding consumables and cast-welding construction

technical field

The invention relates to a cast steel joint of a building steel structure, in particular to a composite joint of a building steel structure using CrNiMn high-alloy welding materials and a cast welding structure, and belongs to the technical field of building steel structures.

Background technique

The steel structure has the advantages of high strength, good toughness, good seismic performance, and fast construction speed. It is very suitable for the development of modern engineering structures that are towering, long-span, and heavy-duty, and engineering applications are increasing. In the development process of space structure, the application of "connection node" of steel structure is becoming wider and wider. With the improvement of casting technology, the cast steel joints are increasingly widely used in our country. Cast steel joints are generally made of integral casting, the joint form is flexible, and the working performance is safe and reliable. Compared with traditional welded joints (such as steel pipe intersecting joints, etc.), cast steel joints avoid the collection of multiple welds of welded joints at the joints, and at the same time, the welds can be arranged far away from the core area of the joint. The stress of the weld is reduced, thus improving the mechanical performance of the structure.

At the same time, the connection method and technology of cast steel node body components and structural main components must also attract attention. Welding is the most common method for connecting cast steel nodes of steel structures to main components. Generally, in the on-site installation and construction of steel structures, the characteristics of the butt joint ports between the cast steel node body and the main components are mainly circular, rectangular or special-shaped structures and other geometric shapes, that is, they are actually "pipe butt joints" or "plate butt joints". "And other welded joint forms. Cast steel joint materials of steel structures are commonly used in cast steel series for welded structures such as G20Mn5 and ZG275-485H. Its carbon equivalent is relatively high (the main calculation element carbon content is 0.17-0.25%), and the supply status is casting + heat treatment. The main components of the steel structure are usually made of low-alloy structural steels such as Q345, Q390, Q420, and Q460. The carbon equivalent is relatively low (the carbon content of the main calculation element is generally ≤0.20%), and the supply status is rolling or rolling + heat treatment , Therefore, the two materials have different microstructures, different grain sizes, and different weldability. The weldability of cast steel is relatively poor, and the weldability of rolled steel is relatively good.

In the butt welding construction between the cast steel node and the main component of the steel structure, due to the large difference in carbon equivalent and metal microstructure between the steel components of cast steel and rolled steel, the mutual The weldability of steel is not ideal, as the construction process of "dissimilar steel welding" is relatively complicated, and it is easy to cause hidden dangers in the quality of welded joints. Especially under the conditions of on-site installation and welding construction, the butt welding of dissimilar materials between the building steel structure cast steel node body member and the structural main member, the overall strength, stiffness, ductility and plasticity and fatigue performance of the butt joints are easier. Restricted and affected by many factors such as welding materials, welding positions, site environment and heat treatment methods, the final result not only increases the difficulty of welding construction, but also increases the comprehensive process cost of its construction.

In summary, the comprehensive technical level of dissimilar steel welding between cast steel node body components and structural main components, and how to ensure the performance of high-quality "dissimilar steel" welded joints, has actually become a technical bottleneck affecting the rapid development of space structures. one.

Contents of the invention

The present invention aims to solve the problems of unsatisfactory weldability between steel members made of cast steel and hot-rolled steel, complicated construction techniques for dissimilar steel welding, and potential hidden dangers in the quality of welded joints during on-site installation and welding construction, and further provides a A composite node of building steel structure using CrNiMn high-alloy welding consumables and cast-welding structure.

The technical scheme that the present invention takes for solving the problems of the technologies described above is:

The building steel structure composite node of the cast-welding structure of the present invention includes a plurality of cast steel body member joints 1-1 and a plurality of structural main body extension members 1-2, and the cast steel body member joints 1-1 and structural main body extension members 1-2 The number of joints 1-1 of each cast steel body component is set to be equal, the free end of each cast steel body member joint 1-1 is welded together with the corresponding structural main body extension member 1-2, and the free end of each cast steel body member joint 1-1 is connected to the corresponding structural main body The extension members 1-2 have the same cross-sectional outline dimensions, and the structure main extension members 1-2 have the same material as the corresponding structural main members.

Further, the length range L of the structural body extension member 1-2 is 250-500 mm.

Further, the free end of each cast steel body component joint 1-1 is provided with a welding groove.

Further, the extension member 1-2 of the structural main body is a circular steel pipe member, a rectangular steel pipe member, an H-shaped member in cross section, an I-shaped member in cross section or an end plate connection member.

Further, the building steel structure composite node also includes a joint liner 2-2, and the joint liner 2-2 is embedded in the connection between the joint 1-1 of the cast steel body member and the extension member 1-2 of the structural main body.

Compared with the prior art, the present invention has the following beneficial effects:

The building steel structure composite node of the cast-welded structure of the present invention is manufactured by pre-welding the structural main body extension component of the same material as the structural main component on the cast steel body component, that is, digesting the process of "welding different steels" into the cast steel node In the stage of factory conditions, it can help improve the quality and reliability of dissimilar steel welded joints;

The invention optimizes the original common structural steel welding consumables into special welding wires of CrNiMn high-alloy welding consumables. Compared with the existing welding process materials, the welded deposited metal has better strength, plasticity and toughness reserves, and can Under the premise of supporting the steel structure strength design principle with better bearing capacity, the welded joint has excellent comprehensive mechanical properties and the overall rigidity and stability of the welded structure, which is conducive to ensuring the long-term service performance of the building steel structure, especially It ensures the anti-fatigue damage ability of the bridge structure under other dynamic load conditions;

The present invention converts the dissimilar steel welding connection process between the cast steel node body component and the structural main component in the original on-site steel structure installation and construction into the structural steel component of the same material between the structural main extension component and the structural main component. Butt welding;

The invention not only facilitates on-site installation of building steel structures and reduces construction costs, but also minimizes hidden dangers in the quality of dissimilar steel welded joints, and is safer, high-quality and efficient; at the same time, it also improves the cost performance of cast steel node products.

Description of drawings

Fig. 1 is the building steel structure composite node schematic diagram (before welding) of cast-welding structure of the present invention;

Fig. 2 is the composite node schematic diagram (after welding) of the building steel structure of cast-welding structure of the present invention;

Fig. 3 is a schematic cross-sectional view of the butt welding of the cast steel member body 1-1 and the main body extension member 1-2 in Embodiment 4 of the present invention (case 1).

Detailed ways

Specific embodiment 1: As shown in Figures 1-3, the building steel structure composite node of the cast-welded structure of this embodiment includes a plurality of cast steel body member joints 1-1 and a plurality of structural main body extension members 1-2, the cast steel The joints 1-1 of the main body member and the extension members 1-2 of the structural main body are arranged in equal numbers, and the free end of each joint 1-1 of the cast steel main body member is butt-welded with the corresponding extension member 1-2 of the structural main body as a whole, allowing each The free end of the joint 1-1 of the cast steel body member and the corresponding extension member 1-2 of the structural main body are not equal in thickness, but it is generally required that the free end of each joint 1-1 of the main body member of the cast steel body and the corresponding extension member 1-2 2 The dimensions of the cross-sectional outer contour of the butt joint are set to be the same, and the material, geometric shape and size of the main structure extension member 1-2 are set to be the same as those of the corresponding structural main member.

In order to simplify the welding construction process, the free end of each cast steel body member joint 1-1 has the same cross-sectional shape as the corresponding structure main body extension member 1-2, and the outer contour dimensions are set to be the same or similar; the plate thickness is the same or similar settings.

In the past, according to the technical conditions of steel castings and structural parts, the traditionally selected welding materials were common low-alloy structural steel welding materials such as ordinary E5015 manual welding electrodes or ER50-6 gas shielded welding wires, so as to meet the requirements of cast steel nodes and The welding strength requirements of the "equal strength design" of structural parts (such as pipe fittings, etc.); due to the steel members of two different parent materials, cast steel and rolled steel, there are large differences in carbon equivalent and metal microstructure , The weldability is not ideal enough. According to the corresponding welding heat treatment process and measures for "dissimilar steel welding", guarantees must be given to avoid welding cracks and obtain better joint mechanical properties.

The dissimilar steel welding material between the joint 1-1 of the cast steel body member and the extension member 1-2 of the structural main body selected by the present invention is optimized as a CrNiMn main alloy system more suitable for dissimilar steel welding between cast steel and rolled steel The special welding wire for austenitic stainless steel, the brand of the special welding wire is: H08Cr20Ni10Mn7Si-ZG, to better replace the original common structural steel welding material (ie ER50-6 in GB/T8110). Compared with the two, its special welding wire welding deposited metal has more excellent strength, plasticity and toughness reserve: the mechanical properties of welding deposited metal are tensile strength Rm≥600N/mm2, elongation after fracture A≥30%, Under the condition of -40℃, the average impact absorbed energy reaches about 90J, which can make the welded joint have excellent comprehensive mechanical properties and the overall rigidity and stability of the welded structure under the premise of supporting the steel structure strength design principle and having better bearing capacity. It is beneficial to ensure the long-term service performance of building steel structures (especially the fatigue damage resistance under dynamic load conditions such as bridge structures). As a chromium-nickel-manganese high alloy, the welding material is mainly austenite at room temperature; and through the joint action of nickel-manganese alloying, it has a more significant ability to dissolve hydrogen and carbon, which can significantly reduce the weld metal and crack susceptibility in the fusion zone. Under appropriate conditions, pre-weld preheating and post-weld heat treatment are not required, which further simplifies the welding construction process.

The present invention uses CrNiMn high-alloy welding consumables and a composite joint of building steel structure constructed by casting and welding technology, aiming at the connection between the cast steel component body 1-1 and the structural main body extension component 1-2, and docking relatively complicated dissimilar steel components The welding process is completed at the factory stage, and CrNiMn high-alloy welding consumables are used for welding to ensure the mechanical properties of high-quality "dissimilar steel" welded joints.

Specific Embodiment 2: As shown in Figures 1-3, the length range L of the structural main body extension member 1-2 of this embodiment is set to 250-500 mm. It is designed in this way to meet the welding specification requirements that the minimum distance between adjacent butt welds on the same bar of the steel structure should be ≥ 200mm. Other components and connections are the same as those in the first embodiment.

Embodiment 3: As shown in FIG. 1 , in this embodiment, the free end of each joint 1-1 of the cast steel body component is provided with a welding groove. This design is convenient for welding and guarantees 2-1 quality of welds. Other compositions and connections are the same as those in Embodiment 1 or 2.

Specific Embodiment Four: As shown in Figure 1 and Figure 2, the structural main body extension member 1-2 of this embodiment is a circular steel pipe member, a rectangular steel pipe member, an H-shaped member in cross section, an I-shaped member or an end plate in cross section Connect components. It is designed in this way for on-site welding with the corresponding main steel structure components. The extension members 1-2 of various structural main bodies can be circular steel pipe members, rectangular steel pipe members or other special-shaped steel members, all of which are one of the embodiments of the present invention. Other components and connections are the same as those in the third embodiment.

Embodiment 5: As shown in Figure 3, the building steel structure composite node described in this embodiment may also include a joint liner 2-2, the connection between the joint 1-1 of the cast steel body member and the extension member 1-2 of the main body of the structure A joint gasket 2-2 is embedded. With such a design, in order to facilitate welding and ensure the quality of the weld 2-1, pad welding can be used. Other compositions and connections are the same as those in Embodiment 1, 2 or 4.

The above content is an explanation of the present invention, and it cannot be determined that the implementation of the present invention is limited thereto. On the premise of not departing from the concept of the present invention, some simple deduction or replacement can also be made, all including "pipe butt joint" or "plate butt joint" "The specific welding joint form should be considered as belonging to the scope of patent protection determined by the claims submitted by the present invention.

Claims (5)

1. A building steel structure composite node adopting CrNiMn high-alloy welding consumables and cast welding structure, it is characterized in that: described building steel structure composite node comprises a plurality of cast steel body component joints (1-1) and a plurality of structural main bodies The number of extension members (1-2), cast steel body member joints (1-1) and structural main body extension members (1-2) are set equal, and the free end of each cast steel body member joint (1-1) is connected to the corresponding The structural main body extension member (1-2) is welded as a whole, and the free end of each cast steel main body member joint (1-1) is set to be the same as the cross-sectional outer contour size of the corresponding structural main body extension member (1-2), The structural main body extension member (1-2) is set with the same material as the corresponding structural main body member. 2. The building steel structure composite node of cast-welding structure according to claim 1, characterized in that: the length range (L) of the extension member (1-2) of the structure main body is 250-500mm. 3. The building steel structure composite node of cast-welding structure according to claim 1 or 2, characterized in that: the free end of each cast steel body component joint (1-1) is provided with a welding bevel. 4. The building steel structure composite node of casting and welding structure according to claim 3, characterized in that: the structure main body extension member (1-2) is a circular steel pipe member, a rectangular steel pipe member, and the cross section is an H-shaped member, and the cross section It is an I-shaped member or an end plate connecting member. 5. The building steel structure composite node of cast-welding structure according to claim 1, 2 or 4, characterized in that: the building steel structure composite node also includes a joint liner (2-2), and the cast steel body member joint A joint gasket (2-2) is embedded in the connection between (1-1) and the structural main body extension member (1-2).