{"id":16017,"date":"2026-09-09T06:46:06","date_gmt":"2026-09-09T06:46:06","guid":{"rendered":"https:\/\/www.hndfcrane.com\/?post_type=posts&#038;p=16017"},"modified":"2026-09-09T09:40:34","modified_gmt":"2026-09-09T09:40:34","slug":"crane-drum-web-to-shaft-weld-crack-cause-analysis","status":"publish","type":"posts","link":"https:\/\/www.hndfcrane.com\/fil\/posts\/crane-drum-web-to-shaft-weld-crack-cause-analysis\/","title":{"rendered":"Crane Drum Web-to-Shaft Weld Crack Cause Analysis"},"content":{"rendered":"<div class=\"wp-block-rank-math-toc-block\" id=\"rank-math-toc\"><p>Talaan ng mga Nilalaman<\/p><nav><ul><li><a href=\"#1-relationship-between-the-crane-drum-web-plate-hub-and-shaft\">1. Relationship Between the Crane Drum, Web Plate, Hub, and Shaft<\/a><\/li><li><a href=\"#2-why-the-crack-appears-near-the-drum-shaft-side\">2. Why the Crack Appears Near the Drum Shaft Side<\/a><ul><li><a href=\"#2-1-stress-concentration-from-a-sudden-section-change\">2.1 Stress Concentration From a Sudden Section Change<\/a><\/li><li><a href=\"#2-2-cyclic-stress-and-impact-loading\">2.2 Cyclic Stress and Impact Loading<\/a><\/li><li><a href=\"#2-3-welding-residual-stress\">2.3 Welding Residual Stress<\/a><\/li><\/ul><\/li><li><a href=\"#3-development-process-of-the-web-plate-crack\">3. Development Process of the Web Plate Crack<\/a><\/li><li><a href=\"#4-common-causes-of-crane-drum-web-to-shaft-weld-cracking\">4. Common Causes of Crane Drum Web-to-Shaft Weld Cracking<\/a><ul><li><a href=\"#4-1-structural-design-factors\">4.1 Structural Design Factors<\/a><\/li><li><a href=\"#4-2-welding-quality-factors\">4.2 Welding Quality Factors<\/a><\/li><li><a href=\"#4-3-operating-loads-beyond-design-conditions\">4.3 Operating Loads Beyond Design Conditions<\/a><\/li><li><a href=\"#4-4-manufacturing-and-assembly-errors\">4.4 Manufacturing and Assembly Errors<\/a><\/li><li><a href=\"#4-5-corrosion-and-environmental-factors\">4.5 Corrosion and Environmental Factors<\/a><\/li><\/ul><\/li><li><a href=\"#5-inspection-repair-and-prevention-measures\">5. Inspection, Repair, and Prevention Measures<\/a><\/li><\/ul><\/nav><\/div>\n\n\n\n<p>This crane drum weld crack analysis examines a case where a long-service crane developed cracking at the weld between the drum web plate and the drum shaft. Although the visible damage appears to be a local metal fatigue problem, the underlying causes may involve structural design, welding procedure, material condition, stress transfer, manufacturing and assembly quality, and operating conditions.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1080\" height=\"720\" src=\"https:\/\/www.hndfcrane.com\/wp-content\/uploads\/2026\/09\/Cracking-of-the-weld-between-the-drum-web-and-the-drum-shaft.jpg\" alt=\"\" class=\"wp-image-16020\"\/><figcaption class=\"wp-element-caption\">Crane drum web-to-shaft weld crack case<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1477\" height=\"1065\" src=\"https:\/\/www.hndfcrane.com\/wp-content\/uploads\/2026\/09\/Schematic-diagram-of-the-cracking-location-in-the-weld-between-the-drum-web-and-the-drum-shaft.png\" alt=\"\" class=\"wp-image-16021\"\/><figcaption class=\"wp-element-caption\">Crack location at the drum web plate and drum shaft weld<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"1-relationship-between-the-crane-drum-web-plate-hub-and-shaft\">1. Relationship Between the Crane Drum, Web Plate, Hub, and Shaft<\/h2>\n\n\n\n<p>In lifting equipment, the drum is a key transmission component used to wind the wire rope and lift or pull the load. The drum shell carries the wire rope, while web plates are usually arranged at both ends of the shell to connect the shell with the hub or shaft.<\/p>\n\n\n\n<p>In a common structure, the hub is welded to the center of the web plate. The hub is then connected to the drum shaft by a key, and the shaft is supported by bearings. In this case, the web plate is welded directly to the drum shaft, and the drum shaft is a long shaft.<\/p>\n\n\n\n<p>The web plate is therefore not only a connecting plate. It also transmits torque and radial force between the drum shell and the drum shaft. General drum failure references often mention fatigue cracks as a replacement condition; this case looks more specifically at why cracking may start around the weld between the web plate and shaft. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"2-why-the-crack-appears-near-the-drum-shaft-side\">2. Why the Crack Appears Near the Drum Shaft Side<\/h2>\n\n\n\n<p>From a mechanical perspective, the drum web plate is a thin plate subjected to torsion, bending, tension-compression, and in-plane shear. Near the drum shaft, several unfavorable conditions may occur at the same time: a sudden section change, weld influence, and cyclic loading.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"2-1-stress-concentration-from-a-sudden-section-change\">2.1 Stress Concentration From a Sudden Section Change<\/h3>\n\n\n\n<p>At the area close to the drum shaft, the structure transitions from a relatively thick shaft to a thinner web plate. For axial positioning and welding, a shaft shoulder is often arranged at the corresponding web plate position. If the transition radius is too small or the transition is not smooth, stress concentration can occur.<\/p>\n\n\n\n<p>Weld defects such as undercut and incomplete penetration can also become crack initiation sources.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"2-2-cyclic-stress-and-impact-loading\">2.2 Cyclic Stress and Impact Loading<\/h3>\n\n\n\n<p>When the drum works, the tensile force generated by wire rope winding is transferred through the drum shell to the web plate, and then to the drum shaft. Each winding and lifting action applies repeated loading to this area, which can act as low-cycle fatigue combined with local impact loading.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"2-3-welding-residual-stress\">2.3 Welding Residual Stress<\/h3>\n\n\n\n<p>When the web plate and drum shaft are welded together, the weld area experiences local high temperature and cooling shrinkage. If the welded structure is not fully annealed or stress-relieved after welding, residual tensile stress remains around the weld. When this residual tensile stress is superimposed with operating load, crack initiation becomes more likely.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"3-development-process-of-the-web-plate-crack\">3. Development Process of the Web Plate Crack<\/h2>\n\n\n\n<p>The crack development can be viewed in three stages.<\/p>\n\n\n\n<p>The first stage is initiation. At the weld root or transition radius, microscopic defects can become crack sources under the combined action of welding residual stress and working stress.<\/p>\n\n\n\n<p>The second stage is propagation. During each lifting operation, the load follows the same transfer path and the peak stress repeats. The crack gradually propagates along the material grain boundary. The fracture surface may show radial or shell-like features.<\/p>\n\n\n\n<p>The third stage is fracture. When the remaining effective section is no longer sufficient to bear the load, sudden brittle fracture may occur, possibly accompanied by tearing of the web plate or separation from the drum shaft.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"4-common-causes-of-crane-drum-web-to-shaft-weld-cracking\">4. Common Causes of Crane Drum Web-to-Shaft Weld Cracking<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-1-structural-design-factors\">4.1 Structural Design Factors<\/h3>\n\n\n\n<p>If the transition between the web plate and the hub or drum shaft does not use a reasonable radius, stress may change abruptly. If the web plate thickness is insufficient, the fatigue strength margin may also be inadequate. A poorly selected weld location can further increase the risk, especially if the weld lies in a high-stress zone rather than a lower-stress area.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-2-welding-quality-factors\">4.2 Welding Quality Factors<\/h3>\n\n\n\n<p>Common weld defects include incomplete penetration, slag inclusion, porosity, undercut, and weld scars. If nondestructive testing such as ultrasonic testing or radiographic testing is not performed after welding, hidden defects may remain in the structure for a long time.<\/p>\n\n\n\n<p>Unoptimized welding parameters and insufficient post-weld stress relief can also increase the risk. For large drum structures, heat treatment for stress relief may be difficult to perform. Vibration stress relief may also be difficult to apply fully, and natural aging or other aging treatment may be affected by project schedule requirements.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-3-operating-loads-beyond-design-conditions\">4.3 Operating Loads Beyond Design Conditions<\/h3>\n\n\n\n<p>Long-term overloading beyond the rated load can increase the fatigue risk of the structure. Frequent starting and braking during lifting can create large impact loads. If the wire rope is arranged improperly on the drum, the force distribution on the drum becomes uneven and local stress may be much higher than the design value.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-4-manufacturing-and-assembly-errors\">4.4 Manufacturing and Assembly Errors<\/h3>\n\n\n\n<p>If the fit between the web plate inner hole and the shaft is too tight or too loose, the initial local stress may become uneven. Assembly stress that has not been fully released may later combine with operating stress.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-5-corrosion-and-environmental-factors\">4.5 Corrosion and Environmental Factors<\/h3>\n\n\n\n<p>When the drum is exposed to a humid or corrosive environment for a long time, the weld area is more prone to corrosion. Corroded areas are also common locations for micro-crack initiation. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"5-inspection-repair-and-prevention-measures\">5. Inspection, Repair, and Prevention Measures<\/h2>\n\n\n\n<p>For existing equipment, magnetic particle testing or ultrasonic testing can be performed regularly around the weld between the web plate and the drum shaft. If cracks are found, the web plate should be repaired by welding or replaced in time, and the wire rope arrangement should be checked to avoid eccentric loading.<\/p>\n\n\n\n<p>For new crane drum design or manufacturing, the transition radius should be optimized and the weld position should be arranged to avoid the maximum stress area as far as possible. The welding procedure should be strictly controlled. Multi-pass welding and symmetrical welding can be used to reduce residual stress, and vibration aging or natural aging may be applied according to actual conditions.<\/p>\n\n\n\n<p>For operation management, long-term overloading and frequent starting and braking should be avoided. The wire rope arrangement should follow the applicable requirements, and worn wire ropes should be replaced regularly.<\/p>\n\n\n\n<p>Crane drum weld cracking is usually not caused by a single factor. A step-by-step review of structure, welding, load, assembly, and environment helps clarify the source of the crack and select corrective measures that fit the actual site conditions.<\/p>","protected":false},"excerpt":{"rendered":"This crane drum weld crack analysis examines a case where a long-service crane developed cracking at the weld between the drum web plate and the drum shaft. Although the visible damage appears to be a local metal fatigue problem, the underlying causes may involve structural design, welding procedure, material condition, stress transfer, manufacturing and assembly [&hellip;]","protected":false},"featured_media":16020,"parent":0,"menu_order":0,"template":"single-SEO-Table.php","posts_category":[197],"posts_tag":[],"acf":[],"_links":{"self":[{"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/xmxposts\/16017"}],"collection":[{"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/xmxposts"}],"about":[{"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/types\/posts"}],"version-history":[{"count":10,"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/xmxposts\/16017\/revisions"}],"predecessor-version":[{"id":16033,"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/xmxposts\/16017\/revisions\/16033"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/media\/16020"}],"wp:attachment":[{"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/media?parent=16017"}],"wp:term":[{"taxonomy":"posts_category","embeddable":true,"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/posts_category?post=16017"},{"taxonomy":"posts_tag","embeddable":true,"href":"https:\/\/www.hndfcrane.com\/fil\/wp-json\/wp\/v2\/posts_tag?post=16017"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}