# JIS B 8363 4-Bolt Flange — Hydraulic and pipe connection type identification

For JIS B 8363 4-Bolt Flange, governing standard is JIS B 8363; region of origin is Japanese Connections; thread type (tapered or parallel) is flange bolts; seat or flare angle is flat surface; seal method is The male connector has a flanged head with a groove for seating an O-ring and either a captive flange or split flange with bolt holes to correspond to the port. The seal is made where the O-ring is compressed between the flanged head and the flat surface of the port. The connection is held by threaded bolts, recorded from its source on 2026-08-13.

- **Connection type:** JIS B 8363 4-Bolt Flange _(verified: appears in the quote below)_
- **Governing standard:** JIS B 8363 _(verified: appears in the quote below)_
- **Region of origin:** Japanese Connections _(our reading, not quoted from the source)_
- **Thread type (tapered or parallel):** flange bolts
- **Seat or flare angle:** flat surface _(verified: appears in the quote below)_
- **Seal method:** The male connector has a flanged head with a groove for seating an O-ring and either a captive flange or split flange with bolt holes to correspond to the port. The seal is made where the O-ring is compressed between the flanged head and the flat surface of the port. The connection is held by threaded bolts. _(verified: appears in the quote below)_
- **Interchangeability notes:** Excluding bolt sizes, SAE J518, JIS B 8363, ISO/DIS 6162 and DIN 20066 are interchangeable.

## What the source says

> JIS B 8363 4-Bolt Flange connections are frequently used in fluid power systems. There are two pressure ratings for JIS B 8363 4-Bolt Flange fittings: Type I Code 61 is the standard series 4-Bolt Flange Type II Code 62 is the 6000 PSI series Each design concept is the same, yet the flanged head diameters and bolt hole spacing are larger for the Type II 6000 PSI connection. Metric and inch bolts are each used with these connectors. The male connector has a flanged head with a groove for seating an O-ring and either a captive flange or split flange with bolt holes to correspond to the port. The female port of the fitting is a smooth, un-threaded port with four bolt holes set in a rectangular pattern in around the port. The seal is made where the O-ring is compressed between the flanged head and the flat surface of the port. The connection is held by threaded bolts.

## Source

- https://brennaninc.com/connection-types/

Last verified: 2026-08-13. Review by: 2028-08-12.
Part of [Hydraulic and pipe connection type identification](https://referencesource.org/industrial-cross-reference-bearings-seals-fittings/).