T.O. 1-1A-9
2-217. CADMIUM WELDING HAZARDS. Fumes and dust accumulating in the air during welding of cadmium plated
metals are major health hazards. Whenever it is necessary to weld cadmium plated parts adequate local exhaust
ventilation will be provided. The minimum amount of air which must be removed from the point of fume origin is 250
cubic feet per minute. The Medical Service Sanitary and Industrial Hygiene Engineers shall approve the exhaust
installation (reference AFP 161-2-2). In many instances it will be easier and safer to remove cadmium from the parts,
accomplish welding, and re-cadmium plate to restore the original corrosion resistance to the part.
2-218. The exhaust load (when welding cadmium parts) will be kept as close to the point origin of cadmium fumes an
possible and never more than 8 inches away.
If local ventilation cannot be supplied, and welding is being done in a small, confined space, the welder will wear an
approved air line respirator.
2-219. Cadmium plated metals can be confused with other electroplated metals. When there is doubt about the
composition of a metal to be welded (including the plating) a sample shall be submitted to a metallurgical or chemical
laboratory for qualitative analysis. Welding will not be performed until the metal/plating is properly identified and
appropriate safety precautions are taken accordingly.
2-220. The fumes (oxides) commonly generated in welding processes originate from several sources such as from the
material being welded, from surface coating applied to the metal and from the electrodes used to weld. The metallic
substance/elements encountered may include iron, zinc, lead, brass, bronze, copper, nickel, arsenic, cadmium,
beryllium, chromium, aluminum, magnesium, manganese, phosphorus, seluim mercury, etc. When these
substances/elements are heated during the welding process, oxides are given off in the form of fumes. All of them
present definite health hazards which shall be controlled by providing adequate ventilation. Cadmium oxide, for
example, is extremely poisonous, particularly in the form of vapor. It has a marked effect on the human respiratory
system. Heavy concentrations cause rawness of the throat, irritation of the mucous membrane and edema of the lungs.
Death or permanent lung damage is the result of prolonged breathing cadmium oxides. Unless the welder is certain of
the metal content, especially of those that are similar in appearance to those containing cadmium, he may become
accidentally exposed to toxic concentrations of cadmium oxide from welding cadmium bearing on plated metals ((see
paragraph 2-210 for ventilation requirements.
2-221. WELDING ON AIRCRAFT. As a general practice, welding in or on aircraft is strictly forbidden, except when
specifically authorized as follows:
a.
As specified in applicable technical data with joint concurrence of Fire Marshal, Ground Safety and Deputy
Commander for Maintenance or his designated representative.
b.
(Deleted)
2-222. Parts requiring repair by welding (other than as cited in paragraph 2-221 when practical, shall be removed from
the aircraft, cleaned of all flammable or toxic deposits and then forwarded to the welding shop for required work.
2-223. FABRICATION OF FERROUS ALLOYS.
2-224. The information furnished in this section is provided as a guide to aid personnel engaged in the use and
application of the ferrous alloys. Due to varied usage of steel products, details and rules related will not fit every
application. In may in many, experimentation trial and further study will be required.
2-225. Personnel assigned to accomplish, application and fabrication must be well trained in fundamentals of metal
forming practices, analysis, properties, corrosion control, machining, plating, welding, heat treat, riveting, painting, blue
print reading, assembly, etc., in accordance with scope of relation to fabrication process. Also, these personnel must
keep constantly abreast of advancing processes for maximum efficiency/proficiency.
2-226. The section of steel for design or application to equipment and component is usually based on the following:
a.
Strength and weight requirement of part/ equipment to be fabricated.
b.
Method to be used for fabrication, i.e., welding, forming, machining, heat treat, etc.
c.
Corrosion resistance to certain chemicals/ environments.
d.
Temperatures to which part will be subjected.
e.
Fatigue properties under cyclic loads, etc.
2-227. The following general rules should be employed in handling and forming:
a
Sheet, sheared/sawed strips and blank shall be handled with care to prevent cutting hands and other parts of the
body.
b.
Sheared or cut edges shall be sanded, filed or polished prior to forming. The removal of rough and sharp edges
is also recommended prior to accomplishing other machining operations to reduce hazards in handling.
Change 9 2-114
