PSI - Issue 59

T. Maydanchuk et al. / Procedia Structural Integrity 59 (2024) 399–406 2 T. Maydanchuk, Y. Lukianchenko, S. Kozulin, V. Porohonko, S. Marynenko/ Structural Integrity Procedia 00 (2019) 000 – 000 1. Introduction Among copper alloys, brass has gained significant industrial popularity due to its combination of high mechanical and technological properties. Compared to pure copper, brass exhibits higher strength, corrosion resistance, improved casting properties, and a higher recrystallization temperature by Freudenberger and Warlimont (2018) and Davis (2001). One of the most widely used brass alloys is the duplex brass grade CuZn37. During operation, components may develop various defects that must be repaired to ensure their continued use. The most common defects include cracks, deep (>0.2 mm) scratches, deep dents, through-holes, and corrosion marks (pits deeper than 0.2 mm). The repair method for each type of defect depends on its nature. Brass falls into the category of materials with limited weldability due to the high probability of porosity, stress corrosion cracking, and cracking. This is attributed to the small temperature range for solidification and the evaporation of zinc by Nayak et al. (2021) and Auwal et al. (2018). In industry, soldering by Zaks (1999), manual arc welding by Nakata (2005), TIG welding by Nayak et al. (2021), and friction welding by Stalin et al. (2020) is widely used for welding and repairing brass. Soldering requires heating brass to high temperatures, which can lead to metal overheating and reduced strength. Covered electrode welding is suitable for brass thicker than 4.0 mm, but the process must be performed using short beads. Moreover, visual control over the weld area and metal formation is challenging with covered electrode welding. Friction welding requires expensive and complex equipment, which may not be suitable for repairing brass products. Therefore, we believe that the most promising process is argon TIG welding, which provides high-quality weld joints, allows for precise heat input control, and is a widely accessible welding method. The objective of this study is to develop a fundamental technology for repairing CuZn37 brass through argon TIG welding, using commercially available filler wires based on metallographic, mechanical, and radiographic analysis of the weld joints. 2. Material and Research Methodology The experimental work was conducted on samples measuring 300x300x4.0 mm made of CuZn37 brass. The chemical composition of the brass is presented in Table 1 by DSTU 15527:2005.

400

Table 1. The grade of the material is CuZn37. Material Chemical composition, wt. % Fe Zn

Cu

0.2

Balance

62-65

CuZn37

Standard industrial wires with a diameter of 3.0 mm were used as filler material (Table 2) by DSTU 15527:2005, DSTU 492:2007, DSTU 18175-78, DSTU 5017:2007, DSTU 1066-90. The TIG welding process was carried out using a non-consumable tungsten electrode with a diameter of 3.0 mm, specifically the WC-20 grade. Argon gas of the first purity grade was used as the shielding gas. Welding was performed using direct current (DC) with the following parameters: welding current (I) ranging from 100 to 180 A, arc voltage (U) ranging from 15 to 16 V, welding speed (V) ranging from 4 to 6 mm/s, and gas flow rate (Q) set at 1200 liters per hour.

Table 2. The grade and main components of the filler materials An example of a table. Material Chemical composition, wt. % Ni Fe Mn Si Ti

Sn

Zn

Cu

5.0-6.0

1.0-1.4

0.3-0.8 1.0-1.5

0.15-0.3 2.7-3.5

0.1-0.3

- -

Balance Balance Balance

CuNiFeSiTi CuSi3Mn1 CuSn4Zn3

- - -

- -

- - -

- -

- -

3.5

2.7

0.2

-

Balance

62-65

CuZn37