First used in Sweden in 1964, the hydrogen reduction process for the conservation of iron involves the passage of pure hydrogen over objects which have been heated in a furnace to atemperature of 600-700° C. It is a technique which can be used when a large number of objects must be treated in a short period of time. The aim of the research was an increase in efficiency of the treatment. Both the reactions occurring within the furnace and the effect of hydrogen reduction on the metallurgical structure of the object being treated were studied. See also AATA 19-1875 for a similar study of this process and 20-957 for reference to entire book.