Metal substrate for catalytic converters

1. A metal substrate for catalytic converter, comprising: a honeycomb core containing a flat metal foil and a corrugated metal foil laminated onto each other; and a metal outer jacket surrounding an outer circumferential surface of the honeycomb core, wherein:

the flat metal foil and the corrugated metal foil disposed in a gas inlet side joining section are joined to each other;

the flat metal foil and the corrugated metal foil disposed in an outer circumferential joining section are joined to each other, the outer circumferential joining section is connected to an axial end section of the gas inlet side joining section;

the gas inlet side joining section extends 5 mm or more and 50% or less of an entire length in an axial direction from a gas inlet side end section of the honeycomb core, across all layers in a radial direction of the honeycomb core;

the outer circumferential joining section extends from the axial end section of the gas inlet side joining section toward a gas outlet side end section of the honeycomb core across two or more layers and ⅓ or less of the total number of layers in the radial direction from an outermost circumference of the honeycomb core;

the outer jacket and the honeycomb core are joined by interposing a joining layer in a gas outlet side end section area formed between the outer jacket and the honeycomb core and extending from the gas outlet side end section of the honeycomb core in the axial direction; when the joining layer has a length P in the axial direction, P fulfills the following formula (A);

the catalytic converter is capable of purifying exhaust gas emitted from a vehicle;

the corrugated metal foil has an impact mitigating section having different wave phases between a front and rear in the axial direction; and the impact mitigating section is formed in a region corresponding to at least the gas inlet side joining section and the outer circumferential joining section;

and

the impact mitigating section is configured such that an offset width being an axial length of a wave having the same phase is 50 mm or less and an amount of phase shift between axially neighboring waves is 0.05 mm or more:

2 mm≤ P≤ 50 mm  (A).

2. The metal substrate for catalytic converter according to claim 1 , wherein the P fulfills the following formula (B):

5 mm≤ P≤ 45 mm  (B).

3. The metal substrate for catalytic converter according to claim 1 , wherein:

the impact mitigating section is formed by connecting continuous bodies, each including trapezoid-like gas channels continuously disposed in an orthogonal plane being orthogonal to the axial direction, in the axial direction with their phases shifted; and

when the gas channel is divided into two regions according to a position corresponding to axially neighboring corrugated metal foils in a view in the axial direction, an area of one region is defined as S 1 , and an area of the other region is defined as S 2 , the area S 1 and the area S 2 are different from each other.

4. The metal substrate for catalytic converter according to claim 3 , wherein the area S 1 and the area S 2 fulfill the following condition formula (C):

1.2 ≤S 1 /S 2≤10  (C).

5. The metal substrate for catalytic converter according to claim 3 , wherein:

the corrugated metal foil includes a pair of tapered sections that constitute side walls of the gas channel; and

when Q is a pitch of the gas channel corresponding to a length of a line connecting respective midpoints of the pair of tapered sections, H is a height of the pair of tapered sections, and a is an angle formed between the radial direction and the tapered section, the following condition formula (D) or (E) is fulfilled:

0.15 ≤H/Q≤ 0.85  (D), and

5°≤α≤45°  (E).

6. The metal substrate for catalytic converter according to claim 3 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

7. The metal substrate for catalytic converter according to claim 2 , wherein:

the impact mitigating section is formed by connecting continuous bodies, each including trapezoid-like gas channels continuously disposed in an orthogonal plane being orthogonal to the axial direction, in the axial direction with their phases shifted; and

when the gas channel is divided into two regions according to a position corresponding to axially neighboring corrugated metal foils in a view in the axial direction, an area of one region is defined as S 1 , and an area of the other region is defined as S 2 , the area S 1 and the area S 2 are different from each other.

8. The metal substrate for catalytic converter according to claim 7 , wherein the area S 1 and the area S 2 fulfill the following condition formula (C):

1.2 ≤S 1 /S 2≤10  (C).

9. The metal substrate for catalytic converter according to claim 4 , wherein:

the corrugated metal foil includes a pair of tapered sections that constitute side walls of the gas channel; and

when Q is a pitch of the gas channel corresponding to a length of a line connecting respective midpoints of the pair of tapered sections, H is a height of the pair of tapered sections, and a is an angle formed between the radial direction and the tapered section, the following condition formula (D) or (E) is fulfilled:

0.15 ≤H/Q≤ 0.85  (D), and

5°≤α≤45°  (E).

10. The metal substrate for catalytic converter according to claim 7 , wherein:

the corrugated metal foil includes a pair of tapered sections that constitute side walls of the gas channel; and

when Q is a pitch of the gas channel corresponding to a length of a line connecting respective midpoints of the pair of tapered sections, H is a height of the pair of tapered sections, and a is an angle formed between the radial direction and the tapered section, the following condition formula (D) or (E) is fulfilled:

0.15 ≤H/Q≤ 0.85  (D), and

5°≤α≤45°  (E).

11. The metal substrate for catalytic converter according to claim 8 , wherein:

the corrugated metal foil includes a pair of tapered sections that constitute side walls of the gas channel; and

when Q is a pitch of the gas channel corresponding to a length of a line connecting respective midpoints of the pair of tapered sections, H is a height of the pair of tapered sections, and a is an angle formed between the radial direction and the tapered section, the following condition formula (D) or (E) is fulfilled:

0.15 ≤H/Q≤ 0.85  (D), and

5°≤α≤45°  (E).

12. The metal substrate for catalytic converter according to claim 4 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

13. The metal substrate for catalytic converter according to claim 5 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

14. The metal substrate for catalytic converter according to claim 7 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

15. The metal substrate for catalytic converter according to claim 8 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

16. The metal substrate for catalytic converter according to claim 9 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

17. The metal substrate for catalytic converter according to claim 10 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).

18. The metal substrate for catalytic converter according to claim 11 , wherein, when L is a length of the trapezoid-like gas channel in the axial direction, the following condition formula (F) is fulfilled:

0.1 mm≤ L≤ 100 mm  (F).