Welded solar roof hook

Specifications

Product Specification Sheet
Product Name	Welded Solar Roof Hook with Rectangular Base Plate for PV Mounting Rails
Part No.	SRH-W01
Category	Solar mounting brackets
Overview	SRH-W01 is a two-piece welded solar roof hook: a rectangular base plate is screwed across the rafter, while a multi-bent Z/gooseneck support arm is fillet-welded onto it to carry the aluminium PV rail with an adjustable slot. Welding allows a thicker arm and a higher load capacity than a purely bent hook.
Version	V1.0 \| 2026-09-15
Material
Main material	SUS304 stainless steel — rectangular base plate plus bent support arm, joined by fillet welding
Grade and standard	SUS304 / AISI 304 / EN 1.4301 plate and flat bar per ASTM A240 or GB/T 3280; welding consumable ER308L （TIG） or A102 electrode
Alternative material	SUS316L （EN 1.4404） arm and plate with ER316L filler for C5 coastal sites; Q235B / Q355B carbon steel with hot-dip galvanizing for inland projects
Raw material form and thickness	Base plate: 5 mm （0.197 in） cold-rolled plate; support arm: 6 mm （0.236 in） flat bar, thickness may be stepped up for snow-load regions
Mechanical properties	Plate ≥ 515 MPa tensile / ≥ 205 MPa yield; weld metal tensile strength ≥ 550 MPa, elongation ≥ 35 %
Material certificate	MTC for plate, flat bar and welding consumables （batch no., chemical and mechanical data） supplied per lot; PMI and weld consumable certificate on request
Service environment and design life	Outdoor rooftop exposure （C4/C5）, 25-year design service life with matched SUS304 fasteners and periodic weld visual inspection
Process
Cutting	CNC laser cutting of the rectangular base plate （rounded corners） and laser/band-saw cutting of the support arm flat bar
Forming （bending）	Press-brake bending of the arm into a Z / gooseneck profile （3–4 bends） so that the tile is cleared and the top flange stays parallel to the base plate
Joining （welding）	Continuous fillet welds on both wide sides of the arm where its vertical leg meets the base plate; fillet leg size 4–5 mm （0.157–0.197 in）, TIG or MIG welding, no full penetration required
Secondary machining	Base plate 6 round holes Ø9 mm （0.354 in） plus 6 slotted holes 11 × 25 mm （0.433 × 0.984 in）; 1 slotted hole 11 × 25 mm in the top rail flange; weld spatter removal and deburring after welding
Surface pre-treatment	Welding slag, spatter and heat tint removed by shot blasting; weld zone pickled to restore the passive film before passivation
Key process control points	Welding jig secures arm perpendicularity to the base plate; weld leg size, throat and start/stop craters controlled; no undercut, crack, porosity or burn-through allowed
Process route	Incoming inspection → laser cutting → deburring → arm bending → welding and weld dressing → shot blasting → pickling and passivation → dimensional and weld inspection → packing
Surface treatment
Treatment method	Shot blasting of the whole part + pickling and passivation （including the weld zone）; no painting or plating for the stainless version
Coating or layer thickness	Passive film only （not measurable）; carbon-steel alternative: hot-dip galvanizing 65–85 µm （2.6–3.3 mil）, local weld-area thickness ≥ 55 µm
Color and appearance	Uniform matte silver-grey; weld beads dressed flat and colour-matched to the base metal, no heat tint, spatter or scale
Standard and salt spray	Weld cleaning and passivation per ASTM A380 / ASTM A967; neutral salt spray （ASTM B117） ≥ 480 h without red rust, weld zone included
Surface roughness	Ra 1.6–3.2 µm on blasted areas; weld beads flush within 0.5 mm （0.020 in） of the parent surface
Pre-treatment	Alkaline degreasing → rinse → weld heat-tint/slag removal → acid pickling → passivation → DI rinse → drying
Tolerance
Overall profile tolerance	General tolerance ISO 2768-m / GB/T 1804-m; base plate length/width ±1.0 mm （0.039 in）; overall height ±1.5 mm （0.059 in）
Hole diameter and position	Round holes Ø9 mm （0.354 in）, +0.2/0 mm; slotted holes 11 × 25 mm （0.433 × 0.984 in）, +0.3/0 mm; hole-to-hole position ±0.5 mm （0.020 in）
Bend angle and radius	Arm bend angle ±1° per bend; inner radius R5 mm ±0.5 mm （0.197 ± 0.020 in）; top flange parallelism to base plate ≤ 1.0 mm （0.039 in）
Weld position tolerance	Arm centred on the base plate within ±1.0 mm （0.039 in）; fillet leg 4–5 mm, throat ≥ 3.5 mm; undercut ≤ 0.2 mm; no crack, porosity or incomplete fusion （visual + sampling macro）
Flatness and straightness	Base plate flatness ≤ 0.5 mm per 100 mm （0.020 in / 3.937 in） after welding; arm perpendicularity deviation ≤ 0.5 mm per 100 mm
Assembly and adjustment fit	Slots provide ±12.5 mm （0.492 in） lateral adjustment; rail bolt clearance hole play ≥ 1.0 mm （0.039 in） for M8/M10
Dimensional basis	Dimensioning and acceptance follow the customer drawing and technical agreement; values above are industry recommended values for reference
Packaging
Surface protection	Each piece wrapped or interleaved with kraft paper/PE film; welded areas protected from impact; no contact with carbon steel during storage
Inner packaging	20 pcs per inner carton with PE-lined divider
Outer packaging	Export 5-ply corrugated carton on fumigation-free plywood pallet, PP strapping and edge protectors
Quantity, carton size and gross weight	50 pcs per carton; carton 400 × 350 × 250 mm （15.75 × 13.78 × 9.84 in）; gross weight approx. 30 kg （66.1 lb）
Marking and shipping marks	Part no. SRH-W01, product name, quantity, lot no., welder/date code, production date, customer shipping mark and MADE IN CHINA
Container loading and stacking	Pallets stackable 4 layers; 1 × 20' GP holds approx. 24 pallets （about 1,200 pcs）
Storage and transport	Indoor dry storage, no chloride or acid/caustic cargo in the same container, original packaging kept until installation
Quality control
Incoming inspection	MTC review and PMI for SUS304 plate/flat bar, thickness 5 mm / 6 mm ±0.2 mm, flatness and surface check; welding consumable batch verification
First article approval	FAI including dimensions, weld leg size, weld visual and macro section on the first welded assembly; approval before batch release
In-process inspection frequency	Weld visual inspection 100 %; dimensional and weld-leg patrol check every 2 hours or every 100 pcs, whichever comes first
Final and outgoing inspection	Sampling per GB/T 2828.1 / ISO 2859-1, AQL 1.0 （major） / 2.5 （minor）; 100 % weld visual, sampled dimensional and weld-leg measurement
Inspection equipment	Weld gauge （fillet leg/throat）, digital caliper and micrometer, height gauge, angle protractor or CMM, roughness tester, salt spray chamber, hardness tester
Records and reports	Weld inspection record （welder ID, leg size, visual result）, dimensional report, MTC, salt spray report and weld macro photo per batch, traceable by lot number
Nonconforming product handling	NCR issued; weld defects are reworked by grinding and re-welding with re-inspection, cracked or plated parts are scrapped; no re-welding of hot-dip galvanized parts without re-galvanizing
Quality system and certificates	Manufactured in an ISO 9001:2015 certified plant in Shandong, China; welding performed per qualified WPS with welder qualification records; no third-party certificate number claimed unless issued for the specific order
Notes	The parameters listed in the table are standard values based on product photographs and our factory's standard manufacturing processes. For items marked as "Recommended Values," as well as all dimensions, materials, and tolerances, the final specifications shall be determined by the customer's drawings (2D/3D), technical agreements, and the results of the first-article inspection.
Drawing Format	3D: .step / .stp / .igs 2D: .dxf / .dwg / .pdf
For Quotation	Drawing + material + surface treatment + quantity + tolerance requirement