Ni-Fe-Cr-Mo Alloy

1 . A structural part comprising an alloy with (in mass %)

Ni 33-35%

Cr 26-28%

Mo 6-7%

Cu 0.5-1.5%

Mn 1.0-4%

Si max. 0.1%

Al 0.01-0.3%

C max. 0.01%

N 0.1-0.25%

B 0.001-0.004%

RE >0 to 1%

Fe remainder, including unavoidable impurities, wherein the structural part has an erosion rate of less than 0.20 mm/year in technical phosphoric acid with a chloride concentration up to 1000 ppm at 100° C.

2 . A structural part comprising an alloy with (in mass %)

Ni 33-35%

Cr 26-28%

Mo 6-7%

Cu 0.5-1.5%

Mn 1.0-4%

Si max. 0.1%

Al 0.01-0.3%

C max. 0.01%

N 0.1-0.25%

B 0.001-0.004%

RE >0 to 1%

Fe remainder, including unavoidable impurities, wherein the structural part, under conditions according to ASTM G 28, Practice A, is resistant to intergranular corrosion and has an erosion rate of less than 0.5 mm/year.

3 . The structural part according to claim 1 , wherein the Ni content (in mass %) is 33.5-34.5%.

4 . The structural part according to claim 1 , wherein the Mn content (in mass %) is 1.5-3.5%.

5 . The structural part according to claim 1 , wherein the Mn content (in mass %) is 1.5-3.0%.

6 . The structural part according to claim 1 , wherein the Mn content (in mass %) is 1.5-2.6%.

7 . The structural part according to claim 1 , wherein the manganese content (in mass %) is 1.5 to 2.0%.

8 . The structural part according to claim 1 , wherein the nitrogen content (in mass %) is 0.14 to 0.22%.

9 . The structural part according to claim 1 , wherein RE is formed by cerium mixed metal in contents between 0.001 and 0.1%.

10 . The structural part according to claim 9 , wherein the grand total of RE is max. 0.06%.

11 . The structural part according to claim 1 , wherein the effect total PREN (=mass % Cr+3.3 mass % Mo+30 mass % N)≧50.

12 . The structural part according to claim 1 , wherein the effect total PREN (=mass % Cr+3.3 mass % Mo+30 mass % N)≧54.