About this Abstract |
Meeting |
2020 AWS Professional Program
|
Symposium
|
2020 AWS Professional Program
|
Presentation Title |
Residual Stress Measurement on High-strength Steel Panels for Shipbuilding Application |
Author(s) |
Yu-Ping Yang, TD Huang, Steve Scholler, Wei Zhang, Charles Fisher |
On-Site Speaker (Planned) |
Yu-Ping Yang |
Abstract Scope |
Shipboard applications of lightweight structures have increased over recent years in both military and commercial vessels. Over the past decade, the production ratio of thin steel (10 mm or less) to thicker plate structures for vessels built has risen. Thin high strength steels such as HSLA-100 and HY-100 have been increasingly used in shipbuilding to reduce ship weight and increase mobility. Residual stress leading to buckling or angular distortion on fabricated panels has been a major concern. There have been many challenges to measure residual stress in shipbuilding because background noise, vibration, and movement during ship construction that may hinder accurate measurements. In addition, a layer of primer which is applied on the steel-plate surface after blasting and a layer of paint after construction have brought more challenges to measure weld residual stress.
A test panel with overall dimensions of 2134mm (7ft.) long and 3048mm (10ft.) wide was designed which includes two plates (5ft. x 7ft.) and four stiffeners. The two plates were butt jointed with a top pass (stiffener side) and a bottom pass (smooth side). Double-sided fillet welds were used to join the stiffeners to the plate. The plate thickness was 6.35mm (1/4in.) and the stiffeners were WT 4x5. Panels were fabricated out of both HSLA-100 and HY100 steel and the stiffener material used was ABS Grade AH36 steel.
Residual stresses on the two welded panels (HSLA-100 and HY-100) and two raw plates were measured with a portable x-ray diffraction (XRD) equipment with grinding and electropolishing to remove the primer at the measured locations. Measurements were conducted near a fillet weld and a seam weld. Measured points were dense near the weld and coarse away from the weld. Based on the measurement results, the following conclusions were drawn:
• HSLA-100 and HY-100 test panels show similar distortion patterns.
• Measured longitudinal residual stresses show a typical residual stress distribution near a weld:
• Tension near weld
• Compression away from the weld
• Measured transverse residual stresses show a typical residual stress distribution near a weld:
• Tension zone of longitudinal residual stress is 4 and 5 times larger than the fillet weld size and seam weld cap size, respectively.
• The compressive stress between the stiffeners were:
• About 71 MPa for HSLA-100
• About 111 MPa for HY-100
• Microstructure phase martensite could affect the measured weld residual stress magnitudes. |
Proceedings Inclusion? |
Definite: Other |