Is a first-class weld a fully penetrative weld?

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In accordance with the provisions on weld quality grades in the \"Code for Design of Steel Structures\" GB 50017-2003, welds should be assigned to different quality grades based on factors such as the importance of the structure, load conditions, type of weld, operating environment, and stress state, following the principles outlined below: 1. In components for which fatigue analysis is required, all butt welds must be fully penetrated; their quality grade shall be as follows: 1) For transverse butt welds or combined T-butt and corner welds where the force acts perpendicular to the weld length, they shall be of grade 1 when under tension and grade 2 when under compression； 2) Longitudinal butt welds whose acting force is parallel to the weld length direction shall be of grade 2. (Thank you for following Dingding Automatic Welding.) 2. In components where fatigue calculation is not required, butt welds that are expected to have the same strength as the base material must be fully penetrated; their quality grade should be at least grade 2 when under tension, and grade 2 is also appropriate when under compression. 3. For crane girders operating under heavy duty conditions or under medium duty conditions with a lifting capacity of Q≥50t, the T-joint welds between the web and the upper flange, as well as those between the upper chord members of the crane truss and the node plates, are required to be fully penetrated. The weld configuration is generally a combination of butt welds and fillet welds, and their quality grade should not be lower than grade 2. 4. For T-joints where full penetration is not required, as well as for butt and fillet combined welds with partial penetration in such joints, and for fillet welds used in lap joints, the quality grade is as follows: 1) For structures that are subjected to dynamic loads and for which fatigue analysis is necessary, as well as for crane girders with a lifting capacity of 50 t or more operating under medium-duty conditions, the visual quality standards for the welds shall meet Grade 2 ； 2) For other structures, the visual quality standard for welds can be grade three. When beams are rigidly connected to columns, full-penetration welds of grade 1 should be used for the connections between beam flanges and columns, the splicing of frame columns, the connection between the column shaft and the base plate in the case of exposed column feet, as well as the splicing of important tensile members such as outrigger trusses; other full-penetration welds shall be of grade 2. The visual quality standard for rootless fillet welds and partially penetrated butt and fillet combined welds shall be grade 2. Gas shielded welding is preferred for primary welds on site.