Robotic Spot Welding of DOCOL 1200M Steel

Abstract

The paper presents robotic spot resistance welding technologies for DOCOL 1200M steel with a thickness of 1.8 mm. DOCOL 1200M steel with a martensitic structure is intended mainly for the production of car bumpers, side beams and other elements ensuring the safety of the user of motor vehicles. The test joints were made on a robotic station equipped with a KUKA KR180 robot and a welding from ARO. The obtained welded joints were subjected to macro and microscopic metallographic tests, hardness measurement and strength tests. It has been shown that for properly selected resistance spot welding, DOCOL 1200M steel joints with a satisfactory strength level can be obtained.

Remote Fibre Laser Welding of Advanced High Strength Martensitic Steel

“…Steel had a carbon equivalent CE of 0.38%, calculated using equation CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 [2,18]. Due to the low weldabilty these steels are welded with a preheating or low energy input or PWHT is used to improve the microstructure and properties of welded joint [11,[13][14][15]18,24].…”

“…can be found in construction elements for passenger safety cell as they allow minimal deformations of body in white (BIW), hence enabling maximum passenger safety [10,11]. The advantage of AHSS steels compared to other materials such as composites, aluminium and magnesium alloys is that they have good formability, recyclability and weldability in addition to their lower price, due to the small amount of alloying elements in steel [2,[12][13][14].…”

“…U/AHSS steels can be welded using various welding technologies, e.g. resistance spot welding, arc welding [13,17], laser welding, electron beam welding and other joining technologies. The welding technology is usually chosen based on the wall thickness of the element in a joint, joint type, quality, quantity, etc.…”

“…The welding technology is usually chosen based on the wall thickness of the element in a joint, joint type, quality, quantity, etc. Thicker work pieces are usually welded using Gas Metal Arc Welding (GMAW) or with shielded metal arc welding (SMAW), although some research is done using high power laser welding [13,18]. Thin steel plates are mostly welded using resistance spot or projection welding [19] and laser welding [20,21], or lately also using Cold Metal Transfer CMT GMAW process [22].…”

“…Furthermore, recently extensive research efforts have been devoted to exploit resistance welding and automated laser welding technologies for joining AHSS. For example, Górka et al [13] used robotic resistance spot welding of 1.8 mm thick Docol ® 1200M steel in a lap joint to determine the structure and properties of joints. In another study, Górka and Ozgowicz [23] laser welded AHSS Docol ® 1200M of 1.8 mm thickness in the overlapped joint configuration.…”