In the post war period, new production technologies developed, markets opened up, and mergers took place among NIZI's customers and suppliers. The second 50 years of NIZI's history contains a significant change in activities. New markets and customers were approached as new products and suppliers were introduced. A new style of doing business developed, and various changes in NIZI's ownership structure occurred.

After the end of the war, trade in local ores with a low content of iron as well as various iron containing products and manganese waste materials carried on for another 10 years. These ores became uncompetitive as rich iron ores from Sweden and other countries became available. At the same time, rich manganese ores were introduced. With the merging of the main European steel groups, NIZI's role in the selling of waste materials diminished.

After 1945, the Allied forces regulated the distribution of Thomas slags at the level of the production plants in order to restore the European agricultural industry. As a consequence, sales of this product gradually declined and after some years, disappeared from NIZI's business. On the other hand, NIZI continued the local sales of nitrided and potassic fertilizers together with its colleagues Mathis Prost S.A. managed by Victor and later on Joseph Prost, until 1996.

In 1945 and 1946, NIZI reestablished ties with Norwegian, French, German, and English producers of ferro-alloys, which were suspended during the war. Very shortly, NIZI became one of the most important distribution channels of ferro-alloys to Western Europe. Pre-war logistical conditions, which oftentimes dictated where ferro-alloys factories were located, became a disadvantage to some producers after the war. Working closely and adhering to a strict discipline of confidentiality, NIZI made a significant contribution towards making these European producers of ferro-alloys more competitive through an efficient distribution system.

One should also bear in mind that long distances required the presence of well introduced companies like NIZI, located near important European endusers. Transportation and communication through telephone, mail, etc. were not well developed at that time. For example, producers located in Norway or in the French Alps had to travel several days in order to meet their customers.

Commencing in 1947, NIZI introduced and represented the Norwegian ferro-silicon producers (grouped into the Norwegian Ferrosilicon Producers Association) in the marketing of ferro-silicon in the Belgium and Luxembourg markets. NIZI also began to represent Norwegian producers of other ferro-alloys, including Tinfos Jernverk A/S, Porsgrunn Elektrometallurgiske A/S, and Ila og Lilleby Smelteverk A/S. Rounding out their palette in the ferro alloy field, NIZI obtained the representation for the Belgian and Luxembourg markets on behalf of the Grünfeld Group and of the French producer Bozel Electrometallurgie S.A. In the Sarre region, NIZI became the exclusive distributor of all French producers of ferro-silicon, ferro-chromium, and special alloys, including Société d'Electro-Chimie d'Electro-Métallurgie et des Aciéries Electriques d'Ugine S.A. and Bozel Electrométallurgie S.A., and also Hauts- Fourneaux, Forges & Aciéries de Pompey S.A. for ferro manganese.

It was also in the years 1950 - 1960 that NIZI began the representation of the South-African producers Samangan for manganese ores and Samancor for certain ferro-alloys through their London offices.

During the fifties and sixties, NIZI began to offer their suppliers and customers flexible marketing and financing services. Acting as an exclusive agent, NIZI brought suppliers and customers closer together. Instead of acting solely as a commission agent, NIZI began to invoice customers directly and provided their suppliers with complete transparency. NIZI offered their suppliers prompt payment in several currencies and thereby took over the responsibility for delcredere and foreign exchange risks as well organising logistics and financing. This flexibility allowed NIZI to offer materials in local currency and with appropriate payment terms, thus assisting NIZI's suppliers to become more competitive.

This evolution in sales policy opened the way to trading new raw materials, such as base metals, which started in the early sixties with deoxidation aluminum. This business developed further with the support of first class producers located in Germany, Great Britain, France, and Scandinavia. Later on, NIZI began to sell magnesium, nickel, and zinc to the steel industry. Following the introduction of these metals in NIZI's traditional markets, sales activities soon expanded all over Western Europe and in later years to Eastern European and the rest of the world.

The evolution from being a sales agent to that of being a distributor also occurred in the field of pig iron. In the 1970s, the production of hematite pig iron in Ijmuiden stopped and thus NIZI's traditional source of pig iron disappeared. During the past 30 years, new pig iron sources were developed. Many of these sources also closed, such as low carbon pig iron from Larvik Smelteverk A/S (Norway), charcoal pig iron from Wundowie (Australia), hematite pig iron from Millom and Barrow ironworks (UK), phosphorous pig iron from Société Miniére & Métallurgique de Musson et Halanzy S.A. (Belgium), pig iron from the Bureau Technique de Fonderie S.A. ("BTF") through low blast furnace in Ougrée (Belgium), hematite pig iron from British Steel Corporation (UK), pig iron from AFS in Trieste (Italy), and pig iron from Lorfonte S.A. in Uckange (France).