The years around 1830 were still difficult for the ironworks in Norway and Moss Jernverk was no exception, and in the years 1836–1840 the blast furnace was idle for a total of three years. Count Wedel-Jarlsberg died in 1840, whereupon his son Harald Wedel-Jarlsberg continued the family business, among them Moss Jernverk. It was now run by a manager, from 1836 the German, Ignatius Wankel. The period of hospitality was ended and the royals were no longer lodged in the administration building when they travelled through Moss. Moss Jernverk increasingly became subordinate to Bærums Jernverk, especially after 1840. The market improved in the 1840s, Norwegian iron strangely enough sold well in North-America, and improvements were done as in similar foreign ironworks. In the second half of the 1840s the market was very good for Moss Jernverk and the production increased strongly: exchange of ore and dividing specialities between the ironworks in Bærum and Moss continued. The production of nails did for example expire in Moss in the 1830s, while the rolling mill was the largest in Norway. By the end of the 1850s the old rolling mill was demolished and a new and much larger one was built, only for the machinery the payment in 1858 was almost 10,999 spesiedaler. This was however the last good period for Norwegian ironworks. After the Crimean War the market became very strained and the Norwegian ironworks were inferior in competition with the Swedish and English works. In the 1860s the Norwegian ironworks were gradually closed down: the price pressure from cheap steel from the very efficient Bessemer process was too strong. Moss Jernverk continued for some years, probably due to the new rolling mill and by the end of the 1860s large amounts of iron were received from Bærum for rolling. A few years after the Franco-Prussian War (1870–1871) a new economical crisis emerged with the Long Depression, which was the final blow for Moss Jernverk. The business was also threatened by the Smaalenene Line, which was decided upon in 1873 and projected right through the ironworks premises. After 1873, the melting of iron ceased. In 1874 and 1875 only the mill and the sawmill were in operation. Moss Jernverk was sold for 115,000 spesiedaler (460,000 Norwegian kroner) in 1875 to the local firm M. Peterson & Søn.