An Important
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Welding Development
The Lenssens Process for Aluminium, Elektron and Iron, in Which Relatively Low Temperatures are Used
A crankcase before and after welding by the Lenssens process. Although badly distorted as a result of the damage, it was straightened during repair, so that the three bearings were in line and the faces dead true.
ASTEP forward in the science of repairing castings by methods which, in the absence of a better term, must be described as welding, appears to be represented by the Lenssens process, now "being practised by the Sharp Welding Co., Park Avenue, West Twyford, London, N.W.10. Judging by the appearance of completed jobs we have examined, and by the reports we have heard of satisfied customers, this system materially reduces the cost and time of repairing.
The inventor is Mr. F. I. Lenssens, a Belgian metallurgist and chemist, who has recently joined the Sharp Welding Co., in order to commercialize the process on which he has been working for over 20 years.
Strictly, the process is not correctly described as welding, or as brazing or soldering, and it is carried out at relatively low temperatures. Mr. Lenssens calls it a " metal penetrating process,or "casting by a homogeneous brazing operation," adding that there is hardly a limit to the types of repair tp damaged aluminium, Elektron, or iron castings that can be effected.
a:-S4 Although the new alloy is applied at a comparatively low temperature, subsequently its melting point is considerably higher than the original figure. Further repairs, however, if they should at any time become necessary, can be done, but, obviously, remelting will require a higher temperature than in the first instance.
In many cases, because of the low temperature used, the repair can be executed with the minimum of dismantling. Furthermore, perfect alignment can be ensured. We are told that, even when bad distortion has occurred as a result of the fracture, the casting can be returned to its original shape with 'such accuracy that machining afterwards is unnecessary.
The crankcase illustrated, Mr. Lenssens informed us, was badly " out" when it came into his hands, but in the finished state the three bearings were perfectly aligned, and neither these nor the cylinder-block face needed to be touched.
Castings of different materials, of course, require different alloys, because expansion and strength characteristics, etc., must be similar. We are not permitted to disclose metallurgical details, but all alloys used are made at the works of the Sharp Welding Co. by the inventor himself.
An approximate time for an average job is five days. The repair illustrated was completed in three days. The cost should be lower than ordinary welding because dismantling and machining are avoided. As for finish, the repair is almost undetectable, except by colour.
When at the works last week a representative of this paper saw more than two dozen engine head, block and crankcase castings in the shops, some already repaired, others in a damaged state, notably badly cracked by frost.
Among concerns now sending work to the company, although it was formed only last summer, we learn that there are seven insurance companies, a number of prominent motor repairers, certain commercial vehicle manufac_ turers' service stations, several fleet owners and more than one welding concern. We are asked to state that the company is prepared to negotiate for the Lenssens-process rights overseas.