Description

Send Inquiry

Product Introduction

DIN2391 ST52 Seamless Honed Tubes is a precision steel tube using high-quality ST52 carbon steel material. It's produced by the seamless manufacturing process to ensure the overall strength and uniformity of the tube. Then it's precision honed, making the inner wall have extremely low surface roughness. Thus, it can significantly reduce the resistance when the fluid passes through and improve the efficiency of the hydraulic or pneumatic system. This kind of tube is widely used in occasions that require high accuracy, high pressure resistance and good sealing, such as construction machinery, metallurgical equipment, automobile manufacturing and other fields.

Product Advantages

High Strength & Durability

DIN2391 ST52 Seamless Honed Tubes use ST52 low-alloy high-strength steel with tensile strength reaching 510-680 MPa, significantly exceeding standard carbon steel (e.g., ST35 at ~360 MPa). Normalizing treatment refines grain structure, eliminating cold-working stress for stable performance under high pressure and repeated loads. This combination extends service life by 30%-40% in harsh conditions like construction machinery and tunnel boring.

Precision Machining

Combining cold drawing/rolling with honing, DIN2391 ST52 Seamless Honed Tubes achieve inner surface smoothness of Ra≤0.4μm and outer diameter tolerance within ±0.05mm. Compared to standard hydraulic tubes (±0.15mm), this precision reduces seal wear by over 90%, preventing oil leaks. A unique phosphating layer (3-5μm) retains corrosion inhibitors without compromising seal fit.

Full Corrosion Protection

DIN2391 ST52 Seamless Honed Tubes feature dual protection: black phosphating inside and optional cold galvanizing outside. This offers 3x better rust resistance than basic-treated pipes. Sealed tube ends block contaminants during storage, ensuring hydraulic system cleanliness.

Specification

Steel Grade	C	SI	Mn	P	S	Cr	Ni	Cu
20#	0.17-0.24	0.17-0.37	0.35-0.65	0.035	0.035	0.250	0.250
45#	0.42-0.50	0.17-0.37	0.50-0.80	0.035	0.035	0.250	0.250
Q345B	≤0.2	≤0.5	1.00-1.60	0.030	0.030	0.030	0.250	0.08
Q345D	≤0.2	≤0.5	1.00-1.60	0.030	0.030	0.250	0.250	0.15
25Mn	0.22-0.29	0.17-0.37	0.70-1.00	0.035	0.035
27SiMn	0.22-0.32	1.10-1.40	1.10-1.40	0.035	0.035	0.300	0.300
E355	≤0.2	≤0.55	≤1.6	0.025	0.025
SAE1026	0.22-0.28	0.15-0.35	0.60-0.90	0.040	0.050

Steel Grade	Rm Mpa	ReH Mpa	Elonggation	cold finished Rm Mpa	cold finished Elonggation
20#	≥520	≥375	≥15	≥550	≥8
45#	≥600	≥520	≥10	≥640	≥5
16Mn(Q345B /D)	≥600	≥520	≥14	≥640	≥5
25Mn	≥600	≥510	≥15	≥640	≥5
27SiMn	≥760	≥610	≥10	≥800	≥5
St45	≥520	≥375	≥15	≥550	≥5
E355(st52)	≥600	≥520	≥14	≥640	≥5
SAE1026	≥600	≥510	≥15	≥640	≥5

Working method	range	ID	H8	H9	H10
cold drawn	25-250	30-50	+0.0390	+0.0620	+0.1000
cold rolling	25-150	50-80	+0.0460	+0.0740	+0.1200
cold drawn-honed	40-250	80-120	+0.0540	+0.0870	+0.1400
cold drawn-SRB	50-250	120-180	+0.0630	+0.1000	+0.1600
cold drawn -polished	40-250	180-250	+0.0720	+0.1150	+0.1850
cold drawn-polish-SRB	50-250	as required	as required	as required	as required

product-750-589

product-750-1159

packaging & shipping

Package	Standard export seaworthy package,suit for all kinds of transport, or as required.
Package	Water-proof Paper + Edge protection + Wooden Pallets
Bulk Size	Any size
Loading Port	Shanghai / Ningbo
Container	1 x 20ft container load Max. 25 Ton, Max. length 5.8m
Container	1 x 40ft container load Max. 30 Ton, Max. Length 11.8m
Delivery Time	About 2 weeks or according to the order's quantity