Welded joint

1. A welded joint obtained by welding using a welding material having a chemical composition including, in mass %, Cr: 15.0 to 35.0%; and Ni: 40.0 to 70.0%, comprising:

a base material having a chemical composition of, in mass %:

C: 0.03 to 0.075%;

Si: 0.6 to 2.0%;

Mn: 0.05 to 2.5%;

P: up to 0.04%;

S: up to 0.015%;

Cr: more than 16.0% and less than 23.0%;

Ni: not less than 20.0% and less than 30.0%;

Cu: 0.5 to 10.0%;

Mo: less than 1%;

Al: up to 0.15%;

N: 0.005 to 0.20%;

O: up to 0.02%;

Ca: 0 to 0.1%;

REM: 0 to 0.15%;

V: not less than 0% and less than 0.5%; and

Nb: 0 to 2%,

a balance being Fe and impurities; and

a first-layer weld metal having a chemical composition including, in mass %, an Fe content ranging from 10 to 40%.

2. The welded joint according to claim 1 , wherein the base material has a chemical composition including, in mass %, one or two selected from the group consisting of:

Ca: 0.005 to 0.1%; and

REM: 0.005 to 0.15%.

3. The welded joint according to claim 1 , wherein the base material has a chemical composition including, in mass %, one or two selected from the group consisting of:

V: not less than 0.002% and less than 0.5%; and

Nb: 0.005 to 0.15%.

4. The welded joint according to claim 1 , wherein the first-layer weld metal has a chemical composition of, in mass %:

C: 0.01 to 0.15%;

Si: 0.01 to 4.0%;

Mn: 0.05 to 3.0%;

P: up to 0.03%;

S: up to 0.015%;

Cr: more than 16.0% and less than 32.0%;

Ni: not less than 20.0%;

Cu: 0.03 to 5.0%;

Al: up to 1.0%;

N: 0.005 to 0.2%;

O: up to 0.02%;

Ti: 0 to 0.5%;

Mo: 0 to 8%;

Nb: 0 to 3%;

Co: 0 to 15%; and

Fe: 10 to 40%,

a balance being impurities.

5. The welded joint according to claim 1 , wherein the welding material has a chemical composition of, in mass %:

C: 0.01 to 0.15%;

Si: up to 4.0%;

Mn: 0.01 to 3.5%;

P: up to 0.03%;

S: up to 0.015%;

Cr: 15.0 to 35.0%;

Ni: 40.0 to 70.0%;

Cu: 0.01 to 4.0%;

Al: 0 to 1.5%;

N: 0.005 to 0.1%;

O: up to 0.03%;

Ti: 0 to 1.0%;

Mo: 0 to 15%;

Nb: 0 to 5%; and

Co: 0 to 15%,

a balance being Fe and impurities.

6. The welded joint according to claim 5 , wherein the welding material has a chemical composition including, in mass %:

Al: 0.15 to 1.5%;

Ti: 0.15 to 1.0%; and

Mo: 7 to 15%,

the chemical composition of the welding material further including at least one of Nb: 0.1 to 5% and Co: 0.1 to 15%.

7. The welded joint according to claim 5 , wherein the welding material has a chemical composition including, in mass %:

Si: 0.5 to 4.0%.

8. A welded joint comprising:

a base material having a chemical composition of, in mass %:

C: 0.03 to 0.075%;

Si: 0.6 to 2.0%;

Mn: 0.05 to 2.5%;

P: up to 0.04%;

S: up to 0.015%;

Cr: more than 16.0% and less than 23.0%;

Ni: not less than 20.0% and less than 30.0%;

Cu: 0.5 to 10.0%;

Mo: less than 1%;

Al: up to 0.15%;

N: 0.005 to 0.20%;

O: up to 0.02%;

Ca: 0 to 0.1%;

REM: 0 to 0.15%;

V: not less than 0% and less than 0.5%; and

Nb: 0 to 2%,

a balance being Fe and impurities; and

a first-layer weld metal having a chemical composition of, in mass %:

C: 0.01 to 0.15%;

Si: 0.01 to 4.0%;

Mn: 0.05 to 3.0%;

P: up to 0.03%;

S: up to 0.015%;

Cr: more than 16.0% and less than 32.0%;

Ni: not less than 20.0%;

Cu: 0.03 to 5.0%;

Al: up to 1.0%;

N: 0.005 to 0.2%;

O: up to 0.02%;

Ti: 0 to 0.5%;

Mo: 0 to 8%;

Nb: 0 to 3%;

Co: 0 to 15%; and

Fe: 10 to 40%,

a balance being impurities.

9. A method of manufacturing a welded joint, comprising the steps of:

preparing a base material having a chemical composition of, in mass %:

C: 0.03 to 0.075%;

Si: 0.6 to 2.0%;

Mn: 0.05 to 2.5%;

P: up to 0.04%;

S: up to 0.015%;

Cr: more than 16.0% and less than 23.0%;

Ni: not less than 20.0% and less than 30.0%;

Cu: 0.5 to 10.0%;

Mo: less than 1%;

Al: up to 0.15%;

N: 0.005 to 0.20%;

O: up to 0.02%;

Ca: 0 to 0.1%;

REM: 0 to 0.15%;

V: not less than 0% and less than 0.5%; and

Nb: 0 to 2%,

a balance being Fe and impurities; and

welding the base material using a welding material having a chemical composition including, in mass %, Cr: 15.0 to 35.0%; and Ni: 40.0 to 70.0%,

wherein the welded joint includes a first-layer weld metal having a chemical composition including, in mass %, an Fe content ranging from 10 to 40%.

10. The method of manufacturing the welded joint according to claim 9 , wherein the first-layer weld metal has a chemical composition of, in mass %:

C: 0.01 to 0.15%;

Si: 0.01 to 4.0%;

Mn: 0.05 to 3.0%;

P: up to 0.03%;

S: up to 0.015%;

Cr: more than 16.0% and less than 32.0%;

Ni: not less than 20.0%;

Cu: 0.03 to 5.0%;

Al: up to 1.0%;

N: 0.005 to 0.2%;

O: up to 0.02%;

Ti: 0 to 0.5%;

Mo: 0 to 8%;

Nb: 0 to 3%;

Co: 0 to 15%; and

Fe: 10 to 40%,

a balance being impurities.

11. The method of manufacturing the welded joint according claim 9 , wherein the welding material has a chemical composition of, in mass %:

C: 0.01 to 0.15%;

Si: up to 4.0%;

Mn: 0.01 to 3.5%;

P: up to 0.03%;

S: up to 0.015%;

Cr: 15.0 to 35.0%;

Ni: 40.0 to 70.0%;

Cu: 0.01 to 4.0%;

Al: 0 to 1.5%;

N: 0.005 to 0.1%;

O: up to 0.03%;

Ti: 0 to 1.0%;

Mo: 0 to 15%;

Nb: 0 to 5%; and

Co: 0 to 15%,

a balance being Fe and impurities.