Wrought Iron Bridge Repair by Welding
Wrought Iron Bridge Repair by Welding
(OP)
I am developing a set or WPS for repairing a wrought iron bridge circa 1880; these procedures must be submitted for approval. I am very concerned about the potential liability and will include a comment, such as below on each WPS. I am looking from comments and guidance from this esteem group.
Base metals are what they are. Wrought Iron circa 1880.
The bridge will be painted so I am not concerned with galvanic corrosion as is typically the case with wrought iron repairs.
Wrought iron is a ductile, tough, fibrous, ferrous material composed of relatively pure iron and silicates, Iron Silicates (Fayalite), Magnesium Silicates (Fosterite) and Iron-Magnesium Silicates (Olivine). These silicates, commonly referred to as slag, are distributed throughout the pure iron in the form of threads or fibers that extend in the rolling direction. The quality of the wrought iron varies because of the range of carbon, manganese, phosphorus, sulfur and silicon that constitutes each individual member. (Sulfur tends to develop hot shortness at elevated temperatures, causing problems during weld repairs. Phosphorous leads to cold shortness, a brittle characteristic at room temperatures or lower). The wrought iron used in the original construction of this bridge has several shortcomings that are a result of a high percentage of phosphorus and sulfur and the directionality of the slag deposition. The slag content may vary and be in excess of 6% by weight. During welding the silicates will start to melt at approximately 1200ºC, this is below the liquidus temperature of the E7018 electrode of approximately 1600ºC. At high slag concentration, the slag may inundate the weld interface surface, resulting in poor fusion, porosity and inclusions. During the welding process the welder shall examine the weld puddle for any signs of excessive slag contamination such as bubbling. If excessive slag contamination is noticed the weld shall be removed my grinding and rewelded.
Ipso facto any repairs by welding shall only be considered as cosmetic, sans any increase in strength, or toughness and with a significant decrease in ductility and possibly a decrease in strength and toughness.
Only full penetration welds are allowed. Fillet and surface type welds typically will peal off wrought iron taking a thin layer of wrought iron at a slag–iron interface.
Comments?
Base metals are what they are. Wrought Iron circa 1880.
The bridge will be painted so I am not concerned with galvanic corrosion as is typically the case with wrought iron repairs.
Wrought iron is a ductile, tough, fibrous, ferrous material composed of relatively pure iron and silicates, Iron Silicates (Fayalite), Magnesium Silicates (Fosterite) and Iron-Magnesium Silicates (Olivine). These silicates, commonly referred to as slag, are distributed throughout the pure iron in the form of threads or fibers that extend in the rolling direction. The quality of the wrought iron varies because of the range of carbon, manganese, phosphorus, sulfur and silicon that constitutes each individual member. (Sulfur tends to develop hot shortness at elevated temperatures, causing problems during weld repairs. Phosphorous leads to cold shortness, a brittle characteristic at room temperatures or lower). The wrought iron used in the original construction of this bridge has several shortcomings that are a result of a high percentage of phosphorus and sulfur and the directionality of the slag deposition. The slag content may vary and be in excess of 6% by weight. During welding the silicates will start to melt at approximately 1200ºC, this is below the liquidus temperature of the E7018 electrode of approximately 1600ºC. At high slag concentration, the slag may inundate the weld interface surface, resulting in poor fusion, porosity and inclusions. During the welding process the welder shall examine the weld puddle for any signs of excessive slag contamination such as bubbling. If excessive slag contamination is noticed the weld shall be removed my grinding and rewelded.
Ipso facto any repairs by welding shall only be considered as cosmetic, sans any increase in strength, or toughness and with a significant decrease in ductility and possibly a decrease in strength and toughness.
Only full penetration welds are allowed. Fillet and surface type welds typically will peal off wrought iron taking a thin layer of wrought iron at a slag–iron interface.
Comments?
Vita sine litteris mors est.





RE: Wrought Iron Bridge Repair by Welding
RE: Wrought Iron Bridge Repair by Welding
Vita sine litteris mors est.
RE: Wrought Iron Bridge Repair by Welding
RE: Wrought Iron Bridge Repair by Welding
RE: Wrought Iron Bridge Repair by Welding
Mechanical repair is better. Add reinforcement, bracing or backing and join by bolts or rivets.
We repaired some overhead steel work in an old plant. After a few trys welding we gave up and did it all mechanical.
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Wrought Iron Bridge Repair by Welding
RE: Wrought Iron Bridge Repair by Welding
Vita sine litteris mors est.
RE: Wrought Iron Bridge Repair by Welding
REFERENCE: Kidder Parker Architects' and Builders' Handbook
Edited by Frank E. Kidder and Harry Parker
18th Edition, John Wiley & Sons, Inc., 1936
Page 412:
"Welds: Wrought iron is more easily welded than steel because the work may be accomplished through a wider range of temperature than with steel. A weld may develop the full strength of the bar, but tests on hand-forged welds on rough tie-bars reported by Kirkaldy gave average values of about 60% of the strength of the bar."
So, while wrought iron may be easy to weld, there seems to be a significant drop in the strength. I would think alternative repairs would give better and safer results.
RE: Wrought Iron Bridge Repair by Welding
RE: Wrought Iron Bridge Repair by Welding
RE: Wrought Iron Bridge Repair by Welding
“Field Welding to Existing Steel Structures” Ricker
h
RE: Wrought Iron Bridge Repair by Welding
Rich2001,
Please refer to this thread thread 181-27567
Thanks,
teb1
RE: Wrought Iron Bridge Repair by Welding
Vita sine litteris mors est.
RE: Wrought Iron Bridge Repair by Welding
Teb1
RE: Wrought Iron Bridge Repair by Welding
The 181 designenates the "CSI (construction) Code Issues Forum."
Vita sine litteris mors est.
RE: Wrought Iron Bridge Repair by Welding
thread725-116788