Industry News

welding uses heat to join metals, and the type of electrical current is very important. There are two main types: AC (Alternating Current) and DC (Direct Current). DC welding gives a very stable and steady arc. This makes it easier to control, especially for thin metals or precise work. AC welding is better for specific jobs, like welding magnetic materials. The choice between AC and DC welding affects cost too. DC welding equipment is often more complex and expensive. AC welding machines are usually simpler and cheaper. Knowing the differences helps in choosing the right method for the material, job requirements, and budget.

Morrow Welding is a leading manufacturer of advanced welding power sources. The company provides high-performance and durable welding machines to the global industrial sector. our products serve key heavy industries like steel, shipbuilding, oil and gas, and metallurgy.

Morrow welding machines offer strong advantages. We have excellent dust and EMI shielding. Components are well protected against oxidation and burnout. Advanced Digital Signal Processing (DSP) control technology ensures stable arcs. For example, the Morrow NBC-500 machine can weld with Φ1.2 solid wire at only 70A. The machines also feature superior High-Speed Pulse welding. This sets a high standard for reliability and efficiency.

This super austenitic stainless steel has low carbon but high alloy content. It shows excellent corrosion resistance in dilute sulfuric acid. Designed for harsh corrosive environments, the material contains high chromium and sufficient nickel. Copper addition enhances its acid resistance. This steel resists chloride crevice corrosion and stress corrosion cracking well. It shows low susceptibility to pitting and cracking. Its pitting resistance outperforms other standard grades. The material offers good processability and weldability. It is suitable for pressure vessel applications.

Overhead Gas Metal Arc Welding (GMAW/MAG), being the most complex spatial position and technically challenging form of fusion welding, requires focused efforts to overcome the effects of gravity on the weld pool. It is prone to defects such as unacceptable weld reinforcement, undercut, slag inclusion, porosity, and lack of fusion. The following sections systematically outline the technical points and quality control requirements for Overhead Gas Metal Arc Welding from the aspects of process preparation, parameter optimization, operation techniques, and defect prevention, providing professional guidance for standardized welder operation.

Titanium alloys, vital in aerospace, deep-sea, and medical fields, rely on precise welding. First, clean base metal grooves (with stainless steel tools, then acetone) and wires; keep assembly gaps ~3mm, misalignment ≤10% of plate thickness. Critical "Three-Stage Protection" uses ≥99.99% argon: shield arc (8-15 L/min), molten pool/root (10-15 L/min), and high-temp welds (20-25 L/min trailing flow) till ≤400°C. For 3-10mm plates, use 80-150A, 3.2mm tungsten electrodes, multi-pass welding; avoid high current (causes HAZ grain coarsening). Test weld first to check silver-white molten pools and uniform seams before batch work.

To prevent porosity in aluminum alloy welding, start with choosing proper methods like TIG and MIG, which ensure good weldability, unlike resistance or gas welding. Adjust process parameters: for TIG, faster speed and proper current reduce hydrogen absorption; for MIG, lower speed allows hydrogen escape. Use AC power for TIG (DC causes issues). Also, thoroughly clean material surfaces, including oxide films, and use high-purity shielding gas to keep air out.

Weld undercut, a groove or depression along weld toes caused by improper welding parameters or operation, reduces the base metal cross-section and leads to stress concentration or cracks; it typically occurs in vertical, horizontal, or overhead welding, existing as outer (groove opening) or inner (groove bottom) types in continuous or intermittent forms. Common causes include excessive current, long arcs, incorrect electrode angles, poor bead movement, improper shielding gas, oversize fillet welds, or arc blow. To prevent it, optimize parameters (lower current, shorter arc), standardize operations (correct posture, adjusted travel speed), and improve processes (multi-pass welding, uniform groove fit-up); for repairs, control heat input and use φ2.0-3.0mm electrodes for overlay to ensure fusion and avoid hydrogen-induced cracks.

Key welding defects in pressure equipment, along with their causes, solutions and prevention, are outlined here. These defects include porosity (from damp welding materials or impure shielding gas), cold cracks (due to hydrogen accumulation and quenching tendency), hot cracks, lack of fusion, incomplete penetration, etc. Solutions involve drying materials, adjusting welding parameters, post-heating; prevention focuses on pre-cleaning workpieces, proper parameter selection and welder training. Pics reserved: Surface Porosity with Cracks, Single Surface Porosity, Transverse Crack.

Copper and its alloys are widely used across various industries due to their excellent electrical and thermal conductivity. However, their welding presents challenges such as difficult fusion caused by high thermal conductivity, significant hot cracking tendency, and porosity issues. The industry has established systematic solutions addressing these characteristics: Regarding welding methods, thin plates are suitable for gas welding or tungsten inert gas arc welding; medium-thick plates are applicable to melting electrode gas shielded welding or electron beam welding; thick plates are recommended for high-power methods like submerged arc welding. For welding materials, specialized electrodes, welding wires, and fluxes must be matched—for instance, bronze-core electrodes are commonly used for brass welding, while inert gas shielded welding predominantly employs argon or argon-helium mixtures. Process-wise, critical steps including pre-weld cleaning, preheating temperature control, and deoxidation crack prevention are emphasized to ensure weld quality and joint performance. These technical measures provide comprehensive support for reliable welding of copper and copper alloys.